// Client owns one serialized Modbus connection. Connect replaces a closed
// connection and selects a unit from one through 247. Reads must return the
// exact requested count. Writes validate their acknowledgements. All operations
// Client owns one serialized Modbus connection. Connect replaces a closed
// connection and selects a unit from one through 247. Reads must return the
// exact requested count. Writes validate their acknowledgements. All operations