vnc对机器进行屏幕打印

i looking to take screen print of vnc machine with golang, my actual function is :

.....

code working, problem is when function connect to vnc server not wait to load vnc image and image black:

.. take print first to finish loading. my neeed is take print screen only after complete loaded.

example code :

VncPrint("1.176.68.198","123456")

how i can fix this problem ?