react native webview 添加header 失效？

Question

<WebView              source={{uri:url,              headers:{'xxx':'content'}}}//失效不起作用          />版本信息如下：Environment:  OS: macOS Sierra 10.12.6  Node: 9.11.1  Yarn: 1.5.1  npm: 5.6.0  Watchman: 4.9.0  Xcode: Xcode 9.2 Build version 9C40b  Android Studio: 3.0 AI-171.4443003Packages: (wanted => installed)  react: ^16.3.0-alpha.1 => 16.3.1  react-native: 0.54.2 => 0.54.2求解答！