Wrap Stream to prevent Close/Dispose in PowerShell classes

IndisposableStreamWrapper.ps1

class IndisposableStream : IO.Stream {
    hidden [IO.Stream] $_inner
  
    IndisposableStream([IO.Stream]$inner) {
        $this._inner = $inner
    }
  
    # proxy (almost) everything back to the inner stream object
    hidden [bool] get_CanRead() { return $this._inner.CanRead }
    hidden [bool] get_CanWrite() { return $this._inner.CanWrite }
    hidden [bool] get_CanSeek() { return $this._inner.CanSeek }
    hidden [long] get_Length() { return $this._inner.Length }
    hidden [long] get_Position() { return $this._inner.Position }
    hidden [void] set_Position([long]$value) { $this._inner.Position = $value }
    
    [long]
    Seek([long]$offset, [IO.SeekOrigin]$origin) { 
        return $this._inner.Seek($offset, $origin)
    }
    
    [void]
    SetLength([long]$length) {
        $this._inner.SetLength($length)
    }
    
    [int]
    Read([byte[]]$buffer, [int]$offset, [int]$count) { 
        return $this._inner.Read($buffer, $offset, $count) 
    }

    [void]
    Write([byte[]]$buffer, [int]$offset, [int]$count) { 
        $this._inner.Write($buffer, $offset, $count) 
    }

    [void]
    Flush() { 
        $this._inner.Flush()
    }

    # ... but shield inner stream from premature closure
    # 
    # Sixel will now be calling either of these without changing 
    # the state of the inner stream object. 
    # This will allow Invoke-WebRequest's clumsy attempt to read
    # it to end to actually succeed (since it remains unclosed) 
    [void]Dispose() {}
    [void]Close() {}
}

# et voila, no more closed stream access error
Invoke-WebRequest -Uri https://pngimg.com/d/brain_PNG99.png -UseBasicParsing | ConvertTo-Sixel -Stream {[IndisposableStream]$_.RawContentStream}