Crate thread_tree

A hierarchical thread pool used for splitting work in a branching fashion.

This thread pool is good for:

• You want to split work recursively in jobs that use approximately the same time.
• You want thread pool overhead to be low

This is not good for:

• You need work stealing
• When you have jobs of uneven size

Structs

• ThreadTree
  A hierarchical thread pool used for splitting work in a branching fashion.
• ThreadTreeCtx
  A level-specific handle to the thread tree, that can be used to inject jobs.