Can fail to get random unused port

[sneurlax]

See cypherstack/stack_wallet#675 for example

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Exception: Failed to get random unused port!
#0      Tor.start (package:tor_ffi_plugin/tor_ffi_plugin.dart:110:9)
<asynchronous suspension>
#1      TorService.start (package:stackwallet/services/tor_service.dart:74:7)
<asynchronous suspension>
#2      main (package:stackwallet/main.dart:179:5)
<asynchronous suspension>

[Cyrix126]

potential fix ?
Foundation-Devices#67