aiostream provides a collection of stream operators that can be
combined to create asynchronous pipelines of operations.

It can be seen as an asynchronous version of itertools, although
some aspects are slightly different. Essentially, all the provided
operators return a unified interface called a stream. A stream is
an enhanced asynchronous iterable providing the following features:

* Operator pipe-lining - using pipe symbol |
* Repeatability - every iteration creates a different iterator
* Safe iteration context - using async with and the stream method
* Simplified execution - get the last element from a stream using await
* Slicing and indexing - using square brackets []
* Concatenation - using addition symbol +