arrow

ARROW-4997: [C#] ArrowStreamReader doesn't consume whole stream and doesn't implement sync read.

When reading from a network stream, ArrowStreamReader doesn't check how many bytes were read, and instead assumes the whole buffer was filled with a single read call. Fixing this to read multiple times to fill the whole buffer.

Also, when consuming a stream only the async read method works. The synchronous method throws NotImplementedException. Implementing the sync method.

Note: this implements a lot of the underlying functionality from #3925. The difference here is that this change doesn't attempt to solve the perf issues with allocating and copying memory multiples times. #3925 is specifically solving that perf issue.

@stephentoub @pgovind @chutchinson

Author: Eric Erhardt <eric.erhardt@microsoft.com>

Closes #4017 from eerhardt/ArrowReaderBlockingIssues and squashes the following commits:

806a0d34 <Eric Erhardt> PR feedback
356a861c <Eric Erhardt> ArrowStreamReader doesn't consume whole stream and doesn't implement sync read.