chore: remove unused clock and mutex helpers

src/time.rs

@@ -14,16 +14,11 @@ pub trait Clock {
 }
 
 pub enum Realtime {}
-pub enum Monotonic {}
 
 impl Clock for Realtime {
     const ID: ClockId = ClockId::Realtime;
 }
 
-impl Clock for Monotonic {
-    const ID: ClockId = ClockId::Monotonic;
-}
-
 pub struct ClockSample<C> {
     time_s: u64,
     time_ns: u64,
@@ -56,10 +51,6 @@ impl<C: Clock> ClockSample<C> {
     pub fn as_secs_f64(&self) -> f64 {
         self.time_s as f64 + self.time_ns as f64 / 1_000_000_000.0
     }
-
-    pub fn to_milliseconds(&self) -> u64 {
-        (self.time_s * 1000) + (self.time_ns / 1000000)
-    }
 }
 
 impl ClockSample<Realtime> {