function isUsingKoreanIME(nativeEvent) {
    return nativeEvent.locale === 'ko';
  } // Track the current IME composition status, if any.
Check if a composition event was triggered by Korean IME.
Our fallback mode does not work well with IE's Korean IME,
so just use native composition events when Korean IME is used.
Although CompositionEvent.locale property is deprecated,
it is available in IE, where our fallback mode is enabled.

@param {object} nativeEvent
@return {boolean}