def process_stream_data(line)
      return true if process_update_message UpdateMessage.parse(line, id, items, fields)
      return true if process_overflow_message OverflowMessage.parse(line, id, items)
      return true if process_end_of_snapshot_message EndOfSnapshotMessage.parse(line, id, items)
    end
def process_stream_data(line)
      return true if process_update_message UpdateMessage.parse(line, id, items, fields)
      return true if process_overflow_message OverflowMessage.parse(line, id, items)
      return true if process_end_of_snapshot_message EndOfSnapshotMessage.parse(line, id, items)
    end
Processes a line of stream data if it is relevant to this subscription. This method is thread-safe and is intended
 to be called by the session's processing thread.

 @param [String] line The line of stream data to process.

 @return [Boolean] Whether the passed line of stream data was processed by this subscription.

 @private