function sendMap(
    key, value, context = undefined, mapType = MapTypes.OBJECT_MAP) {
  let map;
  if (mapType == MapTypes.OBJECT_MAP) {
    map = {};
    map[key] = value;
  } else if (mapType == MapTypes.STRUCTS_MAP) {
    map = new StructsMap();
    map.set(key, value);
  } else if (mapType == MapTypes.ES6_MAP) {
    map = new Map();
    map.set(key, value);
  } else {
    throw new Error('Unsupported map type :)');
  }

  channel.sendMap(map, context);
  mockClock.tick(0);
}
@param {string} key
@param {string} value
@param {string=} context
@param {!MapTypes=} mapType