outgoingMessage.getHeader(name)
name<string> 头部名称- 返回：<string> | <undefined>
获取指定名称的 HTTP 头的值。如果该头未设置，返回的值将是 undefined。
🌐 Gets the value of the HTTP header with the given name. If that header is not
set, the returned value will be undefined.
name <string> 头部名称获取指定名称的 HTTP 头的值。如果该头未设置，返回的值将是 undefined。
🌐 Gets the value of the HTTP header with the given name. If that header is not
set, the returned value will be undefined.