Why does using ref on ShaderMaterial result in a Typescript error stating that "The expected type comes from property 'ref' which is declared here on type 'PolygonMat'"?

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This error occurs because the ref property is not included in the type definition for ShaderMaterial. When trying to use ref on a ShaderMaterial, Typescript cannot confirm that it is a valid property and throws an error. To resolve this, you can create a custom type definition for your ShaderMaterial that includes the ref property.