What is SessionStateProxy and how can I access it in the scenarios
below? In particular I am interested in the instance provided by
default runspace and the way 2 is more practically interesting to me,
as far as I am trying to use it for a custom host.

Code:

Set-StrictMode -Version 2

Write-Host "This does not fail, but SessionStateProxy properties are
null"
$rs = [Management.Automation.Runspaces.Runspace]::DefaultRunspace
$ss = $rs.SessionStateProxy
$ss.InvokeCommand -eq $null
$ss.Path -eq $null

Write-Host "This way simply fails"
Add-Type @'
using System.Management.Automation.Runspaces;
public class Class1 {
public static object GetInvokeCommand()
{
Runspace rs = Runspace.DefaultRunspace;
return rs.SessionStateProxy.InvokeCommand;
}
public static object GetPath()
{
Runspace rs = Runspace.DefaultRunspace;
return rs.SessionStateProxy.Path;
}
}
'@
try { [Class1]::GetInvokeCommand() } catch { Write-Warning $_ }
try { [Class1]::GetPath() } catch { Write-Warning $_ }

[OUTPUT]

This does not fail, but SessionStateProxy properties are null
True
True

This way simply fails
WARNING: Exception calling "GetInvokeCommand" with "0" argument(s): "A
pipeline is already executing.
Concurrent SessionStateProxy method call is not allowed."
WARNING: Exception calling "GetPath" with "0" argument(s): "A pipeline
is already executing.
Concurrent SessionStateProxy method call is not allowed."



[/OUTPUT]