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 +
