message: Change throttle to debounce
  And add an explanation of whyI think one's more apropriate than the
  other for this.
diff: @@ -18,7 +18,7 @@ import React from 'react';
  import PropTypes from 'prop-types';
  import classNames from 'classnames';
  import sdk from '../../../index';
  -import { throttle } from 'lodash';
  +import { debounce } from 'lodash';
  // Invoke validation from user input (when typing, etc.) at most once every N ms.
  const VALIDATION_THROTTLE_MS = 200;
  @@ -118,7 +118,16 @@ export default class Field extends React.PureComponent {
  }
  }
  - validateOnChange = throttle(() => {
  + /*
  + * This was changed from throttle to debounce: this is more traditional for
  + * form validation since it means that the validation doesn't happen at all
  + * until the user stops typing for a bit (debounce defaults to not running on
  + * the leading edge). If we're doing an HTTP hit on each validation, we have more
  + * incentive to prevent validating input that's very unlikely to be valid.
  + * We may find that we actually want different behaviour for registration
  + * fields, in which case we can add some options to control it.
  + */
  + validateOnChange = debounce(() => {
  this.validate({
  focused: true,
  });
  