Where IdealGraphVisualizer graph dumps triggered by Dump or DumpOnError should be written.
The accepted values are:
      File - Dump IGV graphs to the local file system (see DumpPath).
   Network - Dump IGV graphs to the network destination specified by PrintGraphHost and PrintGraphPort.
             If a network connection cannot be opened, dumping falls back to file dumping. 
   Disable - Do not dump IGV graphs.