| index | シェーダーのランダム書き込みターゲットのインデックス | 
| buffer | ComputeBuffer to set as write targe. | 
| preserveCounterValue | CounterValue を変更なしに維持するかどうか | 
| rt | RenderTargetIdentifier to set as write target. | 
Set random write target for Shader Model 4.5 level pixel shaders.
This is the CommandBuffer equivalent of Graphics.SetRandomWriteTarget. The same limitations nad exceptions applies to this call.