title: Using put in callback
body: <p>i'm using react-native with saga, and i want to throw an alert on request succeeded. I want to know how to put an action in the alert callback, and if there is a better way to do this.</p>
  
  <pre><code>function* userRequest(action) {
      try {
          const user = yield call(Api.post, Routes.REQUEST_USER, params);
          yield put({type: types.REQUEST_OK, user: user});
      } catch(e) {
          yield put({type: types.REQUEST_FAILED, user: user});
      }
  }
  
  function* requestOk(action) {
      Alert.alert(
          'User',
          'User request ok!',
          [
              //I know this is wrong
              {text: 'OK', onPress: () =&gt; yield put({type: types.NAVIGATION_BACK})},
          ],
          { cancelable: false }
      )
  }
  
  function* userSaga() {
      yield takeEvery(types.USER_REQUEST, userRequest);
      yield takeEvery(types.REQUEST_OK, requestOk);
  }
  </code></pre>
  
  <p>Thanks you!</p>