Simplified version of ScriptableRenderPass

MyRenderPass.cs

using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

namespace UnityEngine.Experimental.Rendering.Universal {
    public class MyRenderPass :ScriptableRenderPass {

        string m_profilerTag;

        Material m_blitMaterial;

        private RenderTargetIdentifier source { get; set; }
        private RenderTargetHandle destination { get; set; }

        public MyRenderPass(string profilerTag, RenderPassEvent renderPassEvent, Material blitMaterial) {
            m_profilerTag = profilerTag;
            this.renderPassEvent = renderPassEvent;
            m_blitMaterial = blitMaterial;
        }

        public void Setup(RenderTargetIdentifier source, RenderTargetHandle destination) {
            this.source = source;
            this.destination = destination;
        }

        public override void Configure(CommandBuffer cmd, RenderTextureDescriptor cameraTextureDescriptor) {
            if(destination == RenderTargetHandle.CameraTarget)
                cmd.GetTemporaryRT(destination.id, cameraTextureDescriptor);
        }

        public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData) {
            CommandBuffer cmd = CommandBufferPool.Get(m_profilerTag);
            cmd.Clear();

            if(destination == RenderTargetHandle.CameraTarget) {
                Blit(cmd, source, destination.Identifier(), m_blitMaterial, 0);
                Blit(cmd, destination.Identifier(), source);
            } else {
                Blit(cmd, source, destination.Identifier(), m_blitMaterial, 0);
            }
            
            context.ExecuteCommandBuffer(cmd);

            CommandBufferPool.Release(cmd);
        }

        public override void FrameCleanup(CommandBuffer cmd) {
            if(destination == RenderTargetHandle.CameraTarget)
                cmd.ReleaseTemporaryRT(destination.id);
        }

    }

}