Offline_Wire_Protocol

This is the protocol used to communicate with the device
See offline_wire_formats.proto 

As protobuf seems way too bloated for what we want, let's try to make a simpler implementation

According to the docs ( https://protobuf.dev/programming-guides/encoding/ ) protobuf encodes like so:

Varint:
    the MSB of each byte indicates if the next byte is still part of the same value (continuation bit), 
    for instance 11010101 001010101 10001000 would mean that the two bytes are part of the same value, the third byte is already part of some other value

    in other words, if the MSB is 0, we are starting a new value 

    To interpret integers, this example from the docs is great:

    10010110 00000001        // Original inputs.
    0010110  0000001        // Drop continuation bits.
    0000001  0010110        // Put into little-endian order.
    10010110                // Concatenate.
    128 + 16 + 4 + 2 = 150  // Interpret as integer.

    We don't need to care about signed ints as those don't seem to be used

    Bools and enums are just like ints, but their value is either 0 or 1. Seems like one full byte would be used for those

    I32 and I64 are not used as well, but it's similar to varint with the difference that there will always be 4 or 8 bytes regardless of the value 

Wire types:
    There are 6 wire types:
        0 - varint
        1 - I64 (fixed length - 8 bytes)
        2 - LEN (variable length - strings, bytes and so on)
        3 and 4 - {S, E}GROUP - Group start and end, deprecated
        5 - I32 (fixed length - 4 bytes)


Message type:
    Taking the MSB (continuation bit) out we get 7 bits, the last three (LSB side) are the "wire type", the first five (MSB side) indicate the field number 


"length delimited records" (aka strings):
    These have the first byte indicating their type, second being a varint with the size 
 and the remaining (up to the length indicated) are the content, the content doesn't have the continuation bit

Submessages:
    We have a ton of these, messages inside messages, these are represented by type LEN (2) followed by a varint with the size of the submessage

Some nice writing about this

https://carlmastrangelo.com/blog/lets-make-a-varint

https://levelup.gitconnected.com/protobufs-explained-17ed6ba52076