Support []byte

[jadbox]

It would be great to support byte arrays to pass in the user_agent and get user agent sections as bytes. This would help using fasthttp with this library for performance.

[pierrre]

You can convert the []byte to string, or use unsafe.

[jadbox]

The former cost performance and the later is a bit dirty. If it must be done in an unsafe way, I'd recommended doing the unsafe cast inside the lib instead of requiring clients to do the cast.