protobuf 编码之varint/zigzag

发现Avro为了对int、long类型数据压缩，采用Protocol Buffers的ZigZag编码Thrift也采用了类似的算法.

参考:

https://izualzhy.cn/protobuf-encode-varint-and-zigzag
https://www.cnblogs.com/en-heng/p/5570609.html