outgoingMessage.getHeader(name)

• name <string> 标头名称

  ¥name <string> Name of header

• 返回：<string> | <undefined>

  ¥Returns: <string> | <undefined>

获取具有给定名称的 HTTP 标头的值。如果未设置该标头，则返回值为 undefined。

¥Gets the value of the HTTP header with the given name. If that header is not set, the returned value will be undefined.