arrow

ARROW-4220: [Python] Add buffered IO benchmarks with simulated high latency, allow duck-typed files in input_stream/output_stream

These benchmarks will help track possible regressions in buffered IO performance from the Python side.

This also allows objects that implement the right APIs (at least according to `hasattr`) to be passed into these functions.

Closes #5356 from wesm/ARROW-4220 and squashes the following commits:

0307cd919 <Wes McKinney> Code review
bba2aa62c <Wes McKinney> Add buffered IO benchmarks with simulated high latency

Authored-by: Wes McKinney <wesm+git@apache.org>
Signed-off-by: Wes McKinney <wesm+git@apache.org>