optimize the performance of the function appendFormatRFC3339

Author: fx408

src/time/format_rfc3339.go

@@ -55,12 +55,11 @@ func (t Time) appendFormatRFC3339(b []byte, nanos bool) []byte {
 
 	if zone > 3600 {
 		b = appendInt(b, zone/60, 2)
-		b = append(b, ':')
-		b = appendInt(b, zone%60, 2)
+		b = append(b, ':',
+			tensDigit[zone%60], onesDigit[zone%60])
 		return b
 	}
 
-	zone %= 3600
 	b = append(b,
 		tensDigit[zone/60], onesDigit[zone/60],
 		':',