Use unsafe to read uint32

[thani-sh]

binary.Read and binary.Write are usually fine but we can save some cpu by using the unsafe package. You can use the kadirahq/go-tools/hybrid package if you wish. It needs docs but check the test file for an example.

• https://github.com/kadirahq/fastcall/blob/master/conn.go#L35
• https://github.com/kadirahq/fastcall/blob/master/conn.go#L65

Also, try to re-use the hybrid.Uint32.