Avoid inexact read with Stream.Read

System.IO.Stream.Read and System.IO.Stream.ReadAsync might return fewer bytes than requested, resulting in unreliable code if the return value isn't checked.

A call to System.IO.Stream.Read or System.IO.Stream.ReadAsync is made and the return value isn't checked.

To fix a violation, either check the return value (which is the total number of bytes read into the buffer) or call System.IO.Stream.ReadExactly or System.IO.Stream.ReadExactlyAsync instead.

You shouldn't suppress warnings from this rule, as your app might hang if you don't fix the violations.