Hawken

 When I plant the [go-redis](https://github.com/go-redis/redis)'s diagram, it shows struct statefulCmdable implements interface StatefulCmdable. But actually it doesn't implements.  the puml will ignore the nested interface: 

pleaser support snappy uncompress

4

## OS Mac ## VERSION 1.6.1 ## ISSUE DESCRIPTION We use snappy to compress and uncompress the value, please support snappy! I try to use a custom formatter, but it...