all: use time.Since instead of time.Now().Sub

Change-Id: Ie6ab0d9b0933f8c0dda84e7f8ad879e01c4eb337
Reviewed-on: https://go-review.googlesource.com/c/net/+/437095
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: hopehook <hopehook@golangcn.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

Author: hopehook

http2/transport.go

@@ -3049,7 +3049,7 @@ func traceGotConn(req *http.Request, cc *ClientConn, reused bool) {
 	cc.mu.Lock()
 	ci.WasIdle = len(cc.streams) == 0 && reused
 	if ci.WasIdle && !cc.lastActive.IsZero() {
-		ci.IdleTime = time.Now().Sub(cc.lastActive)
+		ci.IdleTime = time.Since(cc.lastActive)
 	}
 	cc.mu.Unlock()
 

trace/trace.go

@@ -395,7 +395,7 @@ func New(family, title string) Trace {
 }
 
 func (tr *trace) Finish() {
-	elapsed := time.Now().Sub(tr.Start)
+	elapsed := time.Since(tr.Start)
 	tr.mu.Lock()
 	tr.Elapsed = elapsed
 	tr.mu.Unlock()