writeAvailable
Invokes block if it is possible to write at least min byte providing byte buffer to it so lambda can write to the buffer up to ByteBuffer.remaining bytes. If there are no min bytes spaces available then the invocation returns 0.
Warning: it is not guaranteed that all of remaining bytes will be represented as a single byte buffer eg: it could be 4 bytes available for write but the provided byte buffer could have only 2 remaining bytes: in this case you have to invoke write again (with decreased min accordingly).
Return
number of consumed bytes or -1 if the block wasn't executed.
Parameters
min
amount of bytes available for write, should be positive
block
to be invoked when at least min bytes free capacity available