Revert "pooled session objects"

This reverts commit a89ff38fe6.

proxy/vmess/encoding/server.go

@@ -99,24 +99,13 @@ type ServerSession struct {
 	responseHeader  byte
 }
 
-var serverSessionPool = sync.Pool{
-	New: func() interface{} { return &ServerSession{} },
-}
-
 // NewServerSession creates a new ServerSession, using the given UserValidator.
 // The ServerSession instance doesn't take ownership of the validator.
 func NewServerSession(validator *vmess.TimedUserValidator, sessionHistory *SessionHistory) *ServerSession {
-	session := serverSessionPool.Get().(*ServerSession)
-	session.userValidator = validator
-	session.sessionHistory = sessionHistory
-	return session
-}
-
-func ReleaseServerSession(session *ServerSession) {
-	session.responseWriter = nil
-	session.userValidator = nil
-	session.sessionHistory = nil
-	serverSessionPool.Put(session)
+	return &ServerSession{
+		userValidator:  validator,
+		sessionHistory: sessionHistory,
+	}
 }
 
 func parseSecurityType(b byte) protocol.SecurityType {