bug: start the client should before set up logging to fix the nil pointer problem

[coldwind007]

Description

in the examples/simple_client/main.go
When you run this program, you will most likely encounter the following problems

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x67579c]

Possible Solution

Placing the start client code block before setup logging can solve this problem

[ozzyozbourne]

I would like to work on this issue

[pottekkat]

@ozzyozbourne feel free to open a PR.