src/vs/workbench/api/common/extHostTypeConverters.ts/_transformScheme
	function _transformScheme(scheme: string | undefined, uriTransformer: IURITransformer | undefined): string | undefined {
		if (uriTransformer && typeof scheme === 'string') {
			return uriTransformer.transformOutgoingScheme(scheme);
		}
		return scheme;
	}