setKeyState(keyName, recordIndex, keyEventState) {
    const existingRecord = this._getKeyState(keyName);

    if (this.isKeyIncluded(keyName)) {
      const previous = KeyEventStateArrayManager.clone(existingRecord[1]);
      const current = KeyEventStateArrayManager.clone(previous);

      KeyEventStateArrayManager.setBit(current, recordIndex, keyEventState);

      this._setKeyState(keyName, [previous, current]);
    } else {
      this.addKey(keyName, keyEventState);
    }

    if (recordIndex === KeyEventType.keyup) {
      this.isEnding = true;
    }
  }
Adds a key event to the current key combination (as opposed to starting a new
keyboard combination).
@param {ReactKeyName} keyName - Name of the key to add to the current combination
@param {KeyEventType} recordIndex - Index in record to set to true
@param {KeyEventState} keyEventState The state to set the key event to