A bug in http.go line 156

[cgang]

	for _, extension := range extensions {
		if extensionHeader, ok := extension.(extensionHeaders); ok {
			if _err := extensionHeader(headers, isObs); err != nil {
				doLog(LEVEL_INFO, fmt.Sprintf("set header with error: %v", _err))
			}
		} else {
			doLog(LEVEL_INFO, "Unsupported extensionOptions")
		}
	}

Note the error returned by extensionHeader(headers, isObs) is captured by _err while not used for comparison.