HadoopStreams to support ByteBufferPositionedReadable input streams

[steveloughran]

Describe the enhancement requested

If a stream declares in its StreamCapabilities that it supports
ByteBufferPositionedReadable, then use it for readFully(ByteBuffer)
All streams in Hadoop 3.0.0 + do declare this.

• use StreamCapabilities to look for ByteBufferReadable.

For detecting ByteBufferReadable, use this probe falling back to the recursive scan.
All streams in the hadoop codebase will report this via StreamCapabilities, but there
may be some third-party streams which do not.

Component(s)

No response

[steveloughran]

I'm implementing this, with tests.