JsonParser parser = new JsonParser();
        JsonElement element = parser.parse("{" +
                "\"body\" : \"" + text + "\"," +
                "\"msgtype\" : \"m.text\"," +
                "\"mirrorIdKey\" : \"" + mirrorIdKey + "\"" +
                "}");
        JsonObject content = element.getAsJsonObject();
        Event event = new Event(Event.EVENT_TYPE_MESSAGE, content, myUserId, roomId);

room.sendEvent(event, new SimpleApiCallback<Void>() {
            @Override
            public void onSuccess(Void aVoid) {
               //some logic
            }
        });