plugin index.raw to send in chunks

The index.raw method for controlling all session output used to send 1 byte at a time. For many systems this is fine, because the network would buffer up a few bytes, then send them in larger chunks. However it was reported that some systems don't do this buffering which greatly slowed down the sending of index.raw data due to the overhead of sending packets with only 1 byte in them. Solution was simple, to buffer up the data within DA and sending that buffer in larger chunks, thus giving the transfer of the same data fewer packets, hence faster transfers.