segfault in sl_lidar_driver.cpp with C1 due to invalid bound channel

[ss32]

Running simple_grabber using the default baudrate of 460800 elicits a segfault on line 993 of sl_lidar_driver.cpp

./simple_grabber --channel --serial /dev/tty/USB0 460800
Error, unexpected error, code: 80008004
Segmentation fault (core dumped)

Output of dmesg --follow

[1551954.612208] simple_grabber[628807]: segfault at 0 ip 000056d7be0eac9e sp 00007ffea64934b0 error 4 in simple_grabber[56d7be0e5000+20000] likely on CPU 9 (core 1, socket 0)
[1551954.612224] Code: 85 c0 74 0e 83 f8 01 0f 84 9e 00 00 00 e9 8b 01 00 00 48 8b 45 98 48 83 c0 28 48 89 c7 e8 d0 28 00 00 48 89 c7 e8 98 ce ff ff <48> 8b 10 48 83 c2 50 48 8b 12 48 89 c7 ff d2 85 c0 0f 94 c0 84 c0

The root issue appears to be trying to access an invalid memory address for the device stemming from getBindedChannel() returning 0x0

Breakpoint 1, sl::SlamtecLidarDriver::setMotorSpeed (this=0x55555559eeb0, speed=0) at src/sl_lidar_driver.cpp:993
993	                if (_transeiver->getBindedChannel()->getChannelType() == CHANNEL_TYPE_SERIALPORT) {
(gdb) p _transeiver->getBindedChannel()->getChannelType() == CHANNEL_TYPE_SERIALPORT
Cannot access memory at address 0x0

(gdb) p _transeiver->getBindedChannel()
$4 = (sl::IChannel *) 0x0

[ss32]

#125 might address this. Applying the patch yields more sane output

./simple_grabber --channel --serial /dev/tty/USB0 460800
Error, cannot bind to the specified serial port /dev/tty/USB0.
Error, unexpected error, code: 80008004