Deprecated. Use IssuePluginCustomTextureUpdateV2 to register TextureUpdate callbacks instead. Callbacks will be passed event IDs kUnityRenderingExtEventUpdateTextureBeginV2 or kUnityRenderingExtEventUpdateTextureEndV2, and data parameter of type UnityRenderingExtTextureUpdateParamsV2.
public void IssuePluginCustomTextureUpdate(IntPtr callback, Texture targetTexture, uint userData)