net: sync net.go with Go 1.18 stdlib

Signed-off-by: Roman Volosatovs <roman@profian.com>

src/net/net.go

@@ -1,4 +1,4 @@
-// The following is copied from Go 1.16 official implementation.
+// The following is copied from Go 1.18 official implementation.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -39,10 +39,10 @@ type Conn interface {
 	// Any blocked Read or Write operations will be unblocked and return errors.
 	Close() error
 
-	// LocalAddr returns the local network address.
+	// LocalAddr returns the local network address, if known.
 	LocalAddr() Addr
 
-	// RemoteAddr returns the remote network address.
+	// RemoteAddr returns the remote network address, if known.
 	RemoteAddr() Addr
 
 	// SetDeadline sets the read and write deadlines associated
@@ -103,8 +103,12 @@ type Listener interface {
 // An Error represents a network error.
 type Error interface {
 	error
-	Timeout() bool   // Is the error a timeout?
-	Temporary() bool // Is the error temporary?
+	Timeout() bool // Is the error a timeout?
+
+	// Deprecated: Temporary errors are not well-defined.
+	// Most "temporary" errors are timeouts, and the few exceptions are surprising.
+	// Do not use this method.
+	Temporary() bool
 }
 
 // OpError is the error type usually returned by functions in the net
@@ -220,6 +224,12 @@ var (
 	_ io.Reader   = (*Buffers)(nil)
 )
 
+// WriteTo writes contents of the buffers to w.
+//
+// WriteTo implements io.WriterTo for Buffers.
+//
+// WriteTo modifies the slice v as well as v[i] for 0 <= i < len(v),
+// but does not modify v[i][j] for any i, j.
 func (v *Buffers) WriteTo(w io.Writer) (n int64, err error) {
 	if wv, ok := w.(buffersWriter); ok {
 		return wv.writeBuffers(v)
@@ -236,6 +246,12 @@ func (v *Buffers) WriteTo(w io.Writer) (n int64, err error) {
 	return n, nil
 }
 
+// Read from the buffers.
+//
+// Read implements io.Reader for Buffers.
+//
+// Read modifies the slice v as well as v[i] for 0 <= i < len(v),
+// but does not modify v[i][j] for any i, j.
 func (v *Buffers) Read(p []byte) (n int, err error) {
 	for len(p) > 0 && len(*v) > 0 {
 		n0 := copy(p, (*v)[0])