MySQL 8.0 C API Developer Guide
int
mysql_session_track_get_next(MYSQL *mysql,
                             enum enum_session_state_type type,
                             const char **data,
                             size_t *length)
          This function fetches additional session state-change
          information received from the server, following that retrieved
          by
          mysql_session_track_get_first().
          The parameters for
          mysql_session_track_get_next()
          are the same as for
          mysql_session_track_get_first().
        
          Following a successful call to
          mysql_session_track_get_first(),
          call
          mysql_session_track_get_next()
          repeatedly until it returns nonzero to indicate no more
          information is available. The calling sequence for
          mysql_session_track_get_next()
          is similar to that for
          mysql_session_track_get_first().
          For more information and an example that demonstrates both
          functions, see
          Section 5.4.74, “mysql_session_track_get_first()”.