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-171.4443003

Packages: (wanted => installed)

  react: ^16.3.0-alpha.1 => 16.3.1

  react-native: 0.54.2 => 0.54.2

求解答！