title: height vs position vs padding in KeyboardAvoidingView "behavior"
body: <p>There is a "behavior" property in KeyboardAvoidingView, e.g.:</p>
  
  <pre><code>import { KeyboardAvoidingView } from 'react-native';
  
  &lt;KeyboardAvoidingView style={styles.container} behavior="padding" enabled&gt;
      ... your UI ...
  &lt;/KeyboardAvoidingView&gt;
  </code></pre>
  
  <p>It can be picked as one of three choices: <code>'height'</code>, <code>'position'</code>, or <code>'padding'</code>.  The difference is not explained <a href="https://facebook.github.io/react-native/docs/keyboardavoidingview.html#behavior" rel="noreferrer">in the documentation</a>.  All it says is that it's not required to set the property, and has a note:</p>
  
  <blockquote>
    <p><em>Note: Android and iOS both interact with this prop differently. Android may behave better when given no behavior prop at all, whereas iOS is the opposite.</em></p>
  </blockquote>
  
  <p>What effect are these settings supposed to have?</p>