various improvements

lib/auth/md5/md5.go

lib/auth/sasl/client.go

lib/auth/sasl/scram/client.go

lib/auth/sasl/scram/server.go

lib/auth/sasl/server.go

lib/pnet/packet/in.go

lib/pnet/packet/packets/v3.0/saslinitialresponse.go

lib/rob/schedulers/v2/pool/pool.go

lib/rob/schedulers/v2/queue/queue.go