Crate sleep

Provides APIs for tasks to sleep for specified time durations.

Key functions:

• The sleep function delays the current task for a given number of ticks.
• The sleep_until function delays the current task until a specific moment in the future.
• The [sleep_periodic] function allows for tasks to be delayed for periodic intervals of time and can be used to implement a period task.

TODO: use regular time-keeping abstractions like Duration and Instant.

Modules

• future
  Asynchronous sleep methods that operate on wakers.

Structs

• Duration
  A Duration type to represent a span of time, typically used for system timeouts.

Functions

• sleep
  Blocks the current task by putting it to sleep for duration ticks.
• sleep_until
  Blocks the current task by putting it to sleep until a specific tick count is reached, given by resume_time.
• unblock_sleeping_tasks
  Remove all tasks that have been delayed but are able to be unblocked now, the current tick count is provided by the system’s interrupt tick count.