def __next__(self):
raise NotImplementedError("<STR_LIT>")<EOL>
Return the next record tuple from the log file. If an unknown SBP
        message type is found, it'll return the raw SBP. If EOF, throws
        exception and then returns to start of file.

        Returns
        -------
        (float, float, object)
          (elapsed msec since beginning of log, UTC timestamp, msg)