text: This directory contains the implementations of lower-level forms of the bulk invocation functions:
  
    * `bulk_invoke_executor`
    * `bulk_async_executor`
    * `bulk_then_executor`
  
  These work like the regular `bulk_invoke` etc. functions, but take an executor
  as a parameter rather than an execution policy. The implementation of
  higher-level forms of `bulk_invoke` and friends lower onto these functions.
  
  