嵌入Google Maps Directions API

Question

我正在尝试嵌入Google Maps Directions API。目前可以正常使用，但我想包括出发时间，因此它可以根据出发时间的交通状况显示出行程需要多长时间。那有可能吗？我已经阅读了一些文档，并指出可以使用“ duration_in_traffic”，但未指定如何使用...有人可以帮忙

  onLoginFacebook = () => {
    LoginManager.logInWithPermissions(['public_profile', 'email'])
      .then(result => {
        if (result.isCancelled) {
          alert('cancelled');
        }
        console.log(
          `login success with permissions: ${result.grantedPermissions.toString()}`,
        );
        return AccessToken.getCurrentAccessToken();
      })
      .then(data => {
        const credential = RNFirebase.auth.FacebookAuthProvider.credential(
          data.accessToken,
        );
        return RNFirebase.auth().signInWithCredential(credential);
      })
      .then(currentFBUser => {
        console.log(`Facebook Login with user: ${JSON.stringify(currentFBUser)}`);
        //NOT WORKING 
        const {currentUser} = firebase.auth();
        const uid = currentUser.uid;
        //NOT WORKING
        firebase.auth().onAuthStateChanged(authedUser => {
          if (authedUser) {
            Actions.home();
          } else {
            Actions.checkAuth();
          }
        });
      })
      .catch(error => {
        console.log(`Login failed with ${error}`);
      });
  };