Yjs varint encoding

y-protocol defines protocol that is used when exchanging data between yjs clients.

Yjs uses varint to encode content, which is similar in protobuf. Yjs encodes unsigned integer within range of 0-2^53-1, which is the max number supported by javascript.

123456=0b111|1000100|1000000
->(1)1000000|(1)1000100|(0)____111
-> 0xc0     | 0xc4     | 0x07

The first bit indicates that whether there's a continuous byte, if it's 0, then the number is finished.

In short, the protocol defines the following methods:

• varUint(number)
• varByteArray(buffer) := varUint(length(buffer)) • buffer
• utf8(string)
• varString(string) := varByteArray(utf8(string))
• json(object) := varString(JSON.stringify(object))