Bug-fixes

• Fix protocol header for unknown protocol (#27)
• Documented a problem with AWS NLB when your server is configured to speak first "AWS Network Load Balancer (NLB) does not push the PPV2 header until the client starts sending the data. This is a problem if your server speaks first. e.g. SMTP, FTP, SSH etc." (#25)

Improvements

• Enable easy Header creation from a source and destination net.Addr. If the net.Addr cannot be represented, the transport information is left unspecified (#31)
• Avoid buffer growing allocation by setting a size of 108 as per RFC "a 108-byte buffer is always enough to store all the line and a trailing zero for string processing" (#27)
• Client example (#37)
• Many code improvements, such as carry package name in errors (a la Go) and stop exporting values that shouldn't be exported (#30 #32 #33)

Thanks

@emersion @mschneider82 @navossoc @viruthagiri