Get or set BlockMode mode.
BlockMode property verifies if operation of writing\reading data to\from serial port does not block thread.
If this property has FALSE value, then operation of reading data from serial port reads symbols, which are located in buffer only and operation of writing data to serial port writes data, which size is not bigger than the output buffer. If the value is TRUE, then operation of writing\reading data to\from port is executed depending on assigned timeouts, this can lead to current thread blocking. By default, parameter has FALSE value.