* * Copyright 2018 gRPC authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http:www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * 

package credentials

import (
	
	
)

type sysConn = syscall.Conn
syscallConn keeps reference of rawConn to support syscall.Conn for channelz. SyscallConn() (the method in interface syscall.Conn) is explicitly implemented on this type, Interface syscall.Conn is implemented by most net.Conn implementations (e.g. TCPConn, UnixConn), but is not part of net.Conn interface. So wrapper conns that embed net.Conn don't implement syscall.Conn. (Side note: tls.Conn doesn't embed net.Conn, so even if syscall.Conn is part of net.Conn, it won't help here).
type syscallConn struct {
sysConn is a type alias of syscall.Conn. It's necessary because the name `Conn` collides with `net.Conn`.
	sysConn
}
WrapSyscallConn tries to wrap rawConn and newConn into a net.Conn that implements syscall.Conn. rawConn will be used to support syscall, and newConn will be used for read/write. This function returns newConn if rawConn doesn't implement syscall.Conn.
func (,  net.Conn) net.Conn {
	,  := .(syscall.Conn)
	if ! {
		return 
	}
	return &syscallConn{
		Conn:    ,
		sysConn: ,
	}