Issue with initialization

[subher0]

Hey! First of all, I want to thank you for your great library, I don't know what I would do without it! Well, not me, my friend, who is a little shy. He was faced with an issue of request initialization and he successfully solved it. Please take a look at line 112 of ModbusReq class, I think it should be one line above its current position. Sorry I'm to lazy to do a pull request

[zgkxzx]

Thank you for your suggestion.