refactor(client): use SignedDuration for effective RTT to support negative values

Simplify RttSample by merging signed and unsigned fields into a single SignedDuration for adjusted and effective RTT. This ensures accurate reporting and statistics when server processing time exceeds raw RTT.

crates/irtt-cli/src/lib.rs

@@ -12,8 +12,8 @@ use std::{
 use clap::{Parser, ValueEnum};
 use irtt_client::{
     ClientConfig, ClientEvent, NegotiatedParams, NegotiationPolicy, OneWayDelaySample, PacketMeta,
-    ReceivedStatsSample, RttSample, ServerTiming, SocketConfig, WarningKind, MAX_DSCP_CODEPOINT,
-    MAX_SERVER_FILL_BYTES, MAX_TTL, MAX_UDP_PAYLOAD_LENGTH,
+    ReceivedStatsSample, RttSample, ServerTiming, SignedDuration, SocketConfig, WarningKind,
+    MAX_DSCP_CODEPOINT, MAX_SERVER_FILL_BYTES, MAX_TTL, MAX_UDP_PAYLOAD_LENGTH,
 };
 use irtt_proto::{Clock, ReceivedStats, StampAt};
 
@@ -397,7 +397,7 @@ pub fn format_human_event_with_options(
             ..
         } => {
             let mut out = format!("seq={seq}");
-            write!(out, "  rtt={}", format_duration(rtt.effective)).unwrap();
+            write!(out, "  rtt={}", format_signed_duration(rtt.effective)).unwrap();
             write_human_one_way(&mut out, *one_way);
             write!(out, "  ipdv={}", format_human_ipdv(stats, *seq)).unwrap();
             if let Some(processing) = server_timing.and_then(|timing| timing.processing) {
@@ -425,7 +425,7 @@ pub fn format_human_event_with_options(
         } => {
             let mut out = format!("late  seq={seq}  highest_seen={highest_seen}  remote={remote}",);
             if let Some(rtt) = rtt {
-                write!(out, "  rtt={}", format_duration(rtt.effective)).unwrap();
+                write!(out, "  rtt={}", format_signed_duration(rtt.effective)).unwrap();
                 write_human_one_way(&mut out, *one_way);
                 write!(out, "  ipdv={}", format_human_ipdv(stats, *seq)).unwrap();
             }
@@ -440,7 +440,7 @@ pub fn format_human_event_with_options(
 
 fn format_rtt_us(event: &ClientEvent) -> Option<String> {
     match event {
-        ClientEvent::EchoReply { rtt, .. } => Some(duration_us(rtt.effective).to_string()),
+        ClientEvent::EchoReply { rtt, .. } => Some(signed_duration_us(rtt.effective).to_string()),
         _ => None,
     }
 }
@@ -585,10 +585,10 @@ fn format_simple(event: &ClientEvent) -> String {
         } => {
             let mut out = format!(
                 "reply seq={seq} remote={remote} rtt_us={}",
-                duration_us(rtt.effective)
+                signed_duration_us(rtt.effective)
             );
-            if let Some(raw) = rtt.adjusted.map(|_| rtt.raw) {
-                write!(out, " raw_rtt_us={}", duration_us(raw)).unwrap();
+            if rtt.adjusted.is_some() {
+                write!(out, " raw_rtt_us={}", duration_us(rtt.raw)).unwrap();
             }
             if let Some(processing) = server_timing.and_then(|timing| timing.processing) {
                 write!(out, " server_processing_us={}", duration_us(processing)).unwrap();
@@ -610,7 +610,7 @@ fn format_simple(event: &ClientEvent) -> String {
         } => {
             let mut out = format!("late seq={seq} highest_seen={highest_seen} remote={remote}",);
             if let Some(rtt) = rtt {
-                write!(out, " rtt_us={}", duration_us(rtt.effective)).unwrap();
+                write!(out, " rtt_us={}", signed_duration_us(rtt.effective)).unwrap();
             }
             out
         }
@@ -656,11 +656,11 @@ fn write_rtt(out: &mut String, rtt: &RttSample) {
         out,
         " raw_rtt_us={} effective_rtt_us={}",
         duration_us(rtt.raw),
-        duration_us(rtt.effective)
+        signed_duration_us(rtt.effective)
     )
     .unwrap();
     if let Some(adjusted) = rtt.adjusted {
-        write!(out, " adjusted_rtt_us={}", duration_us(adjusted)).unwrap();
+        write!(out, " adjusted_rtt_us={}", signed_duration_us(adjusted)).unwrap();
     }
 }
 
@@ -773,6 +773,10 @@ fn duration_us(duration: Duration) -> u128 {
     duration.as_micros()
 }
 
+fn signed_duration_us(duration: SignedDuration) -> i128 {
+    duration.ns / 1_000
+}
+
 fn format_optional_duration(duration: Option<Duration>) -> String {
     duration
         .map(format_duration)
@@ -783,6 +787,18 @@ fn format_duration(duration: Duration) -> String {
     format_ns(duration.as_nanos() as f64)
 }
 
+fn format_signed_duration(duration: SignedDuration) -> String {
+    format_signed_ns(duration.ns as f64)
+}
+
+fn format_signed_ns(ns: f64) -> String {
+    if ns < 0.0 {
+        format!("-{}", format_ns(-ns))
+    } else {
+        format_ns(ns)
+    }
+}
+
 fn format_ns(ns: f64) -> String {
     if ns < 1_000.0 {
         format!("{ns:.0}ns")
@@ -853,10 +869,8 @@ mod tests {
             received_at: test_timestamp(Duration::from_secs(1) + Duration::from_micros(1500)),
             rtt: RttSample {
                 raw: Duration::from_micros(1500),
-                adjusted: Some(Duration::from_micros(1200)),
-                effective: Duration::from_micros(1200),
-                adjusted_signed: Some(SignedDuration { ns: 1_200_000 }),
-                effective_signed: SignedDuration { ns: 1_200_000 },
+                adjusted: Some(SignedDuration { ns: 1_200_000 }),
+                effective: SignedDuration { ns: 1_200_000 },
             },
             server_timing: Some(ServerTiming {
                 receive_wall_ns: Some(1_000),
@@ -880,6 +894,33 @@ mod tests {
         }
     }
 
+    fn negative_adjusted_reply_event() -> ClientEvent {
+        ClientEvent::EchoReply {
+            seq: 8,
+            remote: test_remote(),
+            sent_at: test_timestamp(Duration::from_secs(1)),
+            received_at: test_timestamp(Duration::from_secs(1) + Duration::from_micros(500)),
+            rtt: RttSample {
+                raw: Duration::from_micros(500),
+                adjusted: Some(SignedDuration { ns: -1_500_000 }),
+                effective: SignedDuration { ns: -1_500_000 },
+            },
+            server_timing: Some(ServerTiming {
+                receive_wall_ns: Some(1_000),
+                receive_mono_ns: Some(2_000),
+                send_wall_ns: Some(2_001_000),
+                send_mono_ns: Some(2_002_000),
+                midpoint_wall_ns: None,
+                midpoint_mono_ns: None,
+                processing: Some(Duration::from_micros(2_000)),
+            }),
+            one_way: None,
+            received_stats: None,
+            bytes: 64,
+            packet_meta: PacketMeta::default(),
+        }
+    }
+
     fn late_event_with_meta(packet_meta: PacketMeta) -> ClientEvent {
         ClientEvent::LateReply {
             seq: 4,
@@ -1157,6 +1198,28 @@ mod tests {
         );
     }
 
+    #[test]
+    #[cfg(feature = "stats")]
+    fn streamed_and_summary_rtt_use_signed_effective_policy() {
+        let event = negative_adjusted_reply_event();
+
+        assert_eq!(
+            format_event(&event, OutputMode::RttUs),
+            Some("-1500".to_owned())
+        );
+
+        let machine = format_event(&event, OutputMode::Machine).unwrap();
+        assert!(machine.contains("raw_rtt_us=500"));
+        assert!(machine.contains("effective_rtt_us=-1500"));
+        assert!(machine.contains("adjusted_rtt_us=-1500"));
+
+        let mut collector = irtt_stats::StatsCollector::new(irtt_stats::StatsConfig::finite());
+        collector.process(&event);
+        let summary = collector.snapshot();
+        assert_eq!(summary.rtt.primary.min_ns, Some(-1_500_000));
+        assert_eq!(summary.rtt.adjusted.min_ns, Some(-1_500_000));
+    }
+
     #[test]
     fn machine_prints_stable_key_value_fields() {
         let line = format_event(&reply_event(), OutputMode::Machine).unwrap();

crates/irtt-cli/src/main.rs

@@ -426,9 +426,7 @@ mod tests {
             rtt: RttSample {
                 raw: Duration::from_micros(rtt_us),
                 adjusted: None,
-                effective: Duration::from_micros(rtt_us),
-                adjusted_signed: None,
-                effective_signed: SignedDuration {
+                effective: SignedDuration {
                     ns: i128::from(rtt_us) * 1_000,
                 },
             },
@@ -468,9 +466,7 @@ mod tests {
                 rtt: RttSample {
                     raw: Duration::from_micros(1200),
                     adjusted: None,
-                    effective: Duration::from_micros(1200),
-                    adjusted_signed: None,
-                    effective_signed: SignedDuration { ns: 1_200_000 },
+                    effective: SignedDuration { ns: 1_200_000 },
                 },
                 server_timing: None,
                 one_way: None,
@@ -583,9 +579,7 @@ mod tests {
                 rtt: RttSample {
                     raw: Duration::from_micros(1),
                     adjusted: None,
-                    effective: Duration::from_micros(1),
-                    adjusted_signed: None,
-                    effective_signed: SignedDuration { ns: 1_000 },
+                    effective: SignedDuration { ns: 1_000 },
                 },
                 server_timing: None,
                 one_way: None,

crates/irtt-cli/src/summary.rs

@@ -206,10 +206,8 @@ mod tests {
             received_at,
             rtt: RttSample {
                 raw: Duration::from_micros(1500),
-                adjusted: Some(Duration::from_micros(1200)),
-                effective: Duration::from_micros(1200),
-                adjusted_signed: Some(SignedDuration { ns: 1_200_000 }),
-                effective_signed: SignedDuration { ns: 1_200_000 },
+                adjusted: Some(SignedDuration { ns: 1_200_000 }),
+                effective: SignedDuration { ns: 1_200_000 },
             },
             server_timing: Some(ServerTiming {
                 receive_wall_ns: None,
@@ -254,10 +252,8 @@ mod tests {
             received_at,
             rtt: RttSample {
                 raw: Duration::from_micros(1500),
-                adjusted: Some(Duration::from_micros(1200)),
-                effective: Duration::from_micros(1200),
-                adjusted_signed: Some(SignedDuration { ns: 1_200_000 }),
-                effective_signed: SignedDuration { ns: 1_200_000 },
+                adjusted: Some(SignedDuration { ns: 1_200_000 }),
+                effective: SignedDuration { ns: 1_200_000 },
             },
             server_timing: None,
             one_way: None,

crates/irtt-client/src/client.rs

@@ -727,22 +727,15 @@ fn compute_rtt(
 
     let server_processing = compute_server_processing(ts);
 
-    let adjusted = server_processing.and_then(|sp| raw.checked_sub(sp));
-
-    let effective = adjusted.unwrap_or(raw);
-    let adjusted_signed = server_processing.map(|sp| SignedDuration {
+    let adjusted = server_processing.map(|sp| SignedDuration {
         ns: duration_ns_i128(raw) - duration_ns_i128(sp),
     });
-    let effective_signed = adjusted_signed.unwrap_or(SignedDuration {
-        ns: duration_ns_i128(raw),
-    });
+    let effective = adjusted.unwrap_or_else(|| SignedDuration::from_duration(raw));
 
     RttSample {
         raw,
         adjusted,
         effective,
-        adjusted_signed,
-        effective_signed,
     }
 }
 

crates/irtt-client/src/client/tests/probes_replies/reply_decode.rs

@@ -41,7 +41,11 @@ fn recv_once_decodes_echo_reply_and_emits_event() {
             assert_eq!(*seq, 0);
             assert_eq!(*bytes, echo_packet_len(false, &params));
             assert!(rtt.raw > Duration::ZERO);
-            assert_eq!(rtt.effective, rtt.adjusted.unwrap_or(rtt.raw));
+            assert_eq!(
+                rtt.effective,
+                rtt.adjusted
+                    .unwrap_or_else(|| SignedDuration::from_duration(rtt.raw))
+            );
             assert!(received_stats.is_some());
             let stats = received_stats.as_ref().unwrap();
             assert_eq!(stats.count, Some(42));

crates/irtt-client/src/client/tests/probes_replies/timing_math.rs

@@ -18,13 +18,27 @@ fn server_processing_greater_than_raw_does_not_underflow() {
             ..Default::default()
         },
     );
-    assert!(rtt.adjusted.is_none());
-    assert_eq!(rtt.effective, rtt.raw);
-    assert_eq!(
-        rtt.adjusted_signed,
-        Some(SignedDuration { ns: -999_999_999 })
+    assert_eq!(rtt.adjusted, Some(SignedDuration { ns: -999_999_999 }));
+    assert_eq!(rtt.effective, SignedDuration { ns: -999_999_999 });
+}
+
+#[test]
+fn effective_rtt_uses_raw_when_adjusted_rtt_is_unavailable() {
+    let base = Instant::now();
+    let rtt = compute_rtt(
+        &ClientTimestamp {
+            mono: base,
+            wall: SystemTime::now(),
+        },
+        &ClientTimestamp {
+            mono: base + Duration::from_nanos(42),
+            wall: SystemTime::now(),
+        },
+        &TimestampFields::default(),
     );
-    assert_eq!(rtt.effective_signed, SignedDuration { ns: -999_999_999 });
+
+    assert_eq!(rtt.adjusted, None);
+    assert_eq!(rtt.effective, SignedDuration::from_duration(rtt.raw));
 }
 
 #[test]

crates/irtt-client/src/event.rs

@@ -106,11 +106,15 @@ pub enum WarningKind {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct RttSample {
+    /// Client-observed RTT from send to receive.
     pub raw: Duration,
-    pub adjusted: Option<Duration>,
-    pub effective: Duration,
-    pub adjusted_signed: Option<SignedDuration>,
-    pub effective_signed: SignedDuration,
+    /// Signed RTT adjusted for server processing when server processing is available.
+    pub adjusted: Option<SignedDuration>,
+    /// Signed effective RTT used by stats and CLI reporting.
+    ///
+    /// This is `adjusted` when server processing is available, otherwise `raw`
+    /// converted to a signed duration.
+    pub effective: SignedDuration,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -118,6 +122,20 @@ pub struct SignedDuration {
     pub ns: i128,
 }
 
+impl SignedDuration {
+    pub fn from_duration(duration: Duration) -> Self {
+        Self {
+            ns: i128::try_from(duration.as_nanos()).unwrap_or(i128::MAX),
+        }
+    }
+}
+
+impl From<Duration> for SignedDuration {
+    fn from(value: Duration) -> Self {
+        Self::from_duration(value)
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ServerTiming {
     pub receive_wall_ns: Option<i64>,

crates/irtt-client/tests/protocol_options.rs

@@ -7,7 +7,7 @@ use std::time::Duration;
 
 use irtt_client::{
     Client, ClientConfig, ClientError, ClientEvent, OneWayDelaySample, ReceivedStatsSample,
-    RttSample, ServerTiming,
+    RttSample, ServerTiming, SignedDuration,
 };
 use irtt_proto::{Clock, Params, ReceivedStats, StampAt, TimestampFields};
 
@@ -69,7 +69,10 @@ fn timestamp_modes_drive_reply_event_timing_fields() {
                 assert!(reply.server_timing.is_none());
                 assert!(reply.one_way.is_none());
                 assert!(reply.rtt.adjusted.is_none());
-                assert_eq!(reply.rtt.effective, reply.rtt.raw);
+                assert_eq!(
+                    reply.rtt.effective,
+                    SignedDuration::from_duration(reply.rtt.raw)
+                );
                 assert!(reply.rtt.raw > Duration::ZERO);
             }
             StampAt::Send => {
@@ -349,7 +352,7 @@ fn assert_processing_subtracted(reply: ReplyView<'_>) {
     assert_eq!(processing, Duration::from_nanos(1));
     let adjusted = reply.rtt.adjusted.unwrap();
     assert_eq!(reply.rtt.effective, adjusted);
-    assert!(adjusted < reply.rtt.raw);
+    assert!(adjusted.ns < SignedDuration::from_duration(reply.rtt.raw).ns);
 }
 
 fn assert_one_way_presence(

crates/irtt-stats/src/core.rs

@@ -69,8 +69,8 @@ impl CoreStats {
             StatsEvent::UniqueReply {
                 is_late, sample, ..
             } => self.apply_unique_reply(is_late, *sample),
-            StatsEvent::DuplicateReply { .. } => {
-                self.apply_duplicate_reply();
+            StatsEvent::DuplicateReply { bytes, .. } => {
+                self.apply_duplicate_reply(bytes);
                 EventStatsUpdate::default()
             }
             StatsEvent::Loss { .. } => {
@@ -81,8 +81,8 @@ impl CoreStats {
                 self.apply_warning();
                 EventStatsUpdate::default()
             }
-            StatsEvent::UntrackedLate { .. } => {
-                self.apply_untracked_late();
+            StatsEvent::UntrackedLate { bytes, .. } => {
+                self.apply_untracked_late(bytes);
                 EventStatsUpdate::default()
             }
         }
@@ -121,7 +121,12 @@ impl CoreStats {
             .saturating_add(sample.bytes as u64);
 
         if let Some(count) = sample.received_count {
-            self.packets.server_packets_received = Some(u64::from(count));
+            let count = u64::from(count);
+            self.packets.server_packets_received = Some(
+                self.packets
+                    .server_packets_received
+                    .map_or(count, |current| current.max(count)),
+            );
         }
         if let Some(window) = sample.received_window {
             self.packets.server_received_window = Some(window);
@@ -181,10 +186,11 @@ impl CoreStats {
         updates
     }
 
-    fn apply_duplicate_reply(&mut self) {
+    fn apply_duplicate_reply(&mut self, bytes: usize) {
         self.events.duplicate_replies += 1;
         self.packets.packets_received += 1;
         self.packets.duplicates += 1;
+        self.packets.bytes_received = self.packets.bytes_received.saturating_add(bytes as u64);
     }
 
     fn apply_loss(&mut self) {
@@ -195,8 +201,11 @@ impl CoreStats {
         self.events.warning_events += 1;
     }
 
-    fn apply_untracked_late(&mut self) {
+    fn apply_untracked_late(&mut self, bytes: usize) {
         self.events.untracked_late_replies += 1;
+        self.packets.packets_received += 1;
+        self.packets.late_packets += 1;
+        self.packets.bytes_received = self.packets.bytes_received.saturating_add(bytes as u64);
     }
 
     pub(crate) fn snapshot(&self) -> Snapshot {

crates/irtt-stats/src/lib.rs

@@ -198,6 +198,9 @@ pub struct EventCounts {
     /// Warning events processed.
     pub warning_events: u64,
     /// Late replies that could not be matched to retained in-flight state.
+    ///
+    /// These replies are observed on the socket, but cannot contribute RTT,
+    /// one-way delay, server-processing, or IPDV samples.
     pub untracked_late_replies: u64,
 }
 
@@ -206,19 +209,26 @@ pub struct EventCounts {
 pub struct PacketCounts {
     /// Probe packets sent by the local client.
     pub packets_sent: u64,
-    /// Reply packets received by the local client, including duplicates and late packets.
+    /// Reply packets observed by the local client.
+    ///
+    /// This includes unique measurable replies, duplicate replies, and late
+    /// replies that cannot be matched to retained in-flight state.
     pub packets_received: u64,
-    /// Unique replies received by the local client.
+    /// Unique replies that can contribute timing measurements.
     pub unique_replies: u64,
     /// Duplicate replies received by the local client.
     pub duplicates: u64,
-    /// Late reply packets received by the local client.
+    /// Late reply packets received by the local client, including untracked-late replies.
     pub late_packets: u64,
     /// Probe bytes sent by the local client.
     pub bytes_sent: u64,
-    /// Reply bytes received by the local client.
+    /// Reply bytes observed by the local client.
+    ///
+    /// This includes bytes from unique measurable replies, duplicate replies,
+    /// and untracked-late replies. Per-category byte counts are not currently
+    /// exposed separately.
     pub bytes_received: u64,
-    /// Server-reported packets received, when available.
+    /// Highest cumulative server-reported packets received, when available.
     pub server_packets_received: Option<u64>,
     /// Server-reported receive window, when available.
     pub server_received_window: Option<u64>,

crates/irtt-stats/src/normalization.rs

@@ -22,6 +22,7 @@ pub(crate) enum StatsEvent {
     },
     DuplicateReply {
         at: Instant,
+        bytes: usize,
     },
     Loss {
         at: Instant,
@@ -31,6 +32,7 @@ pub(crate) enum StatsEvent {
     },
     UntrackedLate {
         at: Instant,
+        bytes: usize,
     },
 }
 
@@ -96,11 +98,17 @@ pub(crate) fn normalize_event(event: &ClientEvent) -> Option<StatsEvent> {
                 *bytes,
             )),
         }),
-        ClientEvent::LateReply { received_at, .. } => Some(StatsEvent::UntrackedLate {
+        ClientEvent::LateReply {
+            received_at, bytes, ..
+        } => Some(StatsEvent::UntrackedLate {
             at: received_at.mono,
+            bytes: *bytes,
         }),
-        ClientEvent::DuplicateReply { received_at, .. } => Some(StatsEvent::DuplicateReply {
+        ClientEvent::DuplicateReply {
+            received_at, bytes, ..
+        } => Some(StatsEvent::DuplicateReply {
             at: received_at.mono,
+            bytes: *bytes,
         }),
         ClientEvent::EchoLoss { timeout_at, .. } => Some(StatsEvent::Loss { at: *timeout_at }),
         ClientEvent::Warning { at, .. } => Some(StatsEvent::Warning { at: at.mono }),
@@ -115,10 +123,10 @@ impl StatsEvent {
         match self {
             Self::Sent { at, .. }
             | Self::UniqueReply { at, .. }
-            | Self::DuplicateReply { at }
+            | Self::DuplicateReply { at, .. }
             | Self::Loss { at }
             | Self::Warning { at }
-            | Self::UntrackedLate { at } => *at,
+            | Self::UntrackedLate { at, .. } => *at,
         }
     }
 }
@@ -148,11 +156,11 @@ impl ReplySample {
         received_stats: Option<ReceivedStatsSample>,
         bytes: usize,
     ) -> Self {
-        let rtt_primary_ns = signed_duration_ns(rtt.effective_signed);
+        let rtt_primary_ns = signed_duration_ns(rtt.effective);
         Self {
             bytes,
             rtt_raw_ns: duration_ns_i128(rtt.raw),
-            rtt_adjusted_ns: rtt.adjusted_signed.map(signed_duration_ns),
+            rtt_adjusted_ns: rtt.adjusted.map(signed_duration_ns),
             send_delay_ns: one_way
                 .and_then(|sample| sample.client_to_server)
                 .map(duration_ns_i128),

crates/irtt-stats/tests/common/mod.rs

@@ -13,19 +13,13 @@ pub fn ts(ms: u64) -> ClientTimestamp {
 }
 
 pub fn rtt(raw_ms: u64, effective_ms: i128) -> RttSample {
+    let effective = SignedDuration {
+        ns: effective_ms * 1_000_000,
+    };
     RttSample {
         raw: Duration::from_millis(raw_ms),
-        adjusted: u64::try_from(effective_ms).ok().map(Duration::from_millis),
-        effective: u64::try_from(effective_ms)
-            .ok()
-            .map(Duration::from_millis)
-            .unwrap_or_else(|| Duration::from_millis(raw_ms)),
-        adjusted_signed: Some(SignedDuration {
-            ns: effective_ms * 1_000_000,
-        }),
-        effective_signed: SignedDuration {
-            ns: effective_ms * 1_000_000,
-        },
+        adjusted: Some(effective),
+        effective,
     }
 }
 

crates/irtt-stats/tests/stats.rs

@@ -49,7 +49,7 @@ fn cumulative_rtt_uses_signed_effective_and_tracks_raw() {
 }
 
 #[test]
-fn late_unique_counts_and_duplicates_do_not_update_measurements() {
+fn late_unique_counts_and_duplicates_do_not_update_duplicate_measurements() {
     let mut collector = StatsCollector::new(StatsConfig::finite());
     collector.process(&sent(0, ts(0)));
     collector.process(&sent(1, ts(10)));
@@ -68,6 +68,7 @@ fn late_unique_counts_and_duplicates_do_not_update_measurements() {
     assert_eq!(snapshot.packets.unique_replies, 2);
     assert_eq!(snapshot.packets.duplicates, 1);
     assert_eq!(snapshot.packets.late_packets, 1);
+    assert_eq!(snapshot.packets.bytes_received, 64 + 64 + 64);
     assert_eq!(snapshot.rtt.primary.count, 2);
     assert_eq!(snapshot.loss.lost_packets, 0);
     assert_eq!(snapshot.loss.duplicate_percent, 100.0 / 3.0);
@@ -210,6 +211,20 @@ fn server_processing_and_one_way_require_available_samples() {
     assert_eq!(snapshot.server_processing.processing.count, 1);
     assert_eq!(snapshot.one_way_delay.send_delay.count, 1);
     assert_eq!(snapshot.events.untracked_late_replies, 1);
+    assert_eq!(snapshot.packets.packets_received, 2);
+    assert_eq!(snapshot.packets.unique_replies, 1);
+    assert_eq!(snapshot.packets.late_packets, 1);
+    assert_eq!(snapshot.packets.bytes_received, 128);
+}
+
+#[test]
+fn older_cumulative_server_receive_count_does_not_regress() {
+    let mut collector = StatsCollector::new(StatsConfig::finite());
+    collector.process(&reply(1, 10, 10));
+    collector.process(&late_reply(0, 10, 10));
+
+    let snapshot = collector.snapshot();
+    assert_eq!(snapshot.packets.server_packets_received, Some(2));
 }
 
 #[test]