Yjs varint encoding

^[1]

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^[2].

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

[1] ttps://github.com/yjs/y-protocols/blob/master/PROTOCOL.md

[2] ttps://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER

[1]

[2]