fixed pdu check bug in RX
fixed pdu check bug in RX
kerr-huang/SMPP34,BradburyLab/smpp34,nezorflame/go-smpp,0x19/smpp34,VDVsx/go-smpp,jbuchbinder/smpp34,fiorix/go-smpp,CodeMonkeyKevin/smpp34,fiorix/smpp34