src/vs/workbench/services/userData/common/fileUserDataProvider.ts/FileUserDataProvider/writeFile
class FileUserDataProvider:	writeFile(resource: URI, content: Uint8Array, opts: FileWriteOptions): Promise<void> {
		if (hasReadWriteCapability(this.fileSystemProvider)) {
			return this.fileSystemProvider.writeFile(this.toFileSystemResource(resource), content, opts);
		}
		throw new Error('not supported');
	}