const MockMediaKeySession = function(video, keySystem) {
EventEmitter.call(this);
this.sessionId = "";
this._vid = video;
this._key = keySystem;
this._con = mergeStatic(
onKeyMessage(video),
onKeyAdded(video),
onKeyError(video)
).subscribe((evt) => this.trigger(evt.type, evt));
};
const SessionProxy = function(mk) {
EventEmitter.call(this);
this.sessionId = "";
this._mk = mk;
};