Roslibjs time clock

Hello everyone,
I’m working on measuring transmission time of tf2_web_republisher in the Internet (Algeria Telecom) I wanted to know how fast websocket will transmit tf and the relation between the amount of transmitted data and time delivery. To do that I think I should either use wallClock and synchronize the client and server clocks (I dont know if tf will work correctly if I don’t use ros runtime’ clock), or synchronize the client to the ros runtime’ clock, but in this case I can not find how to get to roslibjs client clock. Is there any ROS utility which can help me synchronizing roslibjs time clock with ROS clock. Thank you very much!