session
IN: The session for the host and port to talk to.
data_writer
IN: Function callback to store the retrieved data locally.
cookie
IN: Opaque data delivered to the data_writer callback to identify this data cookie.
oid
IN: An identifier of the data record to retrieve.
firstbyte
IN: First byte of data range to retrieve.
lastbyte
IN: Last byte of data range to retrieve, or -1 for the end of the record.