Running PiSharpGpio on Raspberry Pi and Mac results in a File Not Found exception in LibGpio.Export( BroadcomPinNumber pinNumber) when trying to open the file stream for the "export" file.
The attempt to open /tmp/RasPiGpio/export fails since the file doesn't exist (the directory does exist).
When opening a FileStream in FileMode.Truncate the file must already exist.