BootInstant instances provide a monotonic clock.
On Fuchsia, BootInstant uses zx::BootInstant::get().
FakeTime instances return the last value that was configured by testing code via set_ticks()
or add_ticks()
. Upon initialization, they return 0.
IncrementingFakeTime automatically increments itself by increment_by
before each call to self.now()
.
MonotonicInstant instances provide a monotonic clock.
On Fuchsia, MonotonicInstant uses zx::MonotonicInstant::get().
UtcInstant instances return the Rust system clock value each time now() is called.