     7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
00 | Fixed prefix 'R' (52h)        | Length, 16bit unsigned int, big endian                        | Data, length bytes         ...
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nn  ...                                                                                                                            |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
