Crate wmark

Structs

• Closer
  Closer holds the two things we need to close a thread and wait for it to finish: a chan to tell the thread to shut down, and a WaitGroup with which to wait for it to finish shutting down.
• WaterMark
  WaterMark is used to keep track of the minimum un-finished index. Typically, an index k becomes finished or “done” according to a WaterMark once done(k) has been called

Enums

• WaterMarkError
  Error type for watermark.