src/vs/platform/files/browser/htmlFileSystemProvider.ts/HTMLFileSystemProvider/mkdir
class HTMLFileSystemProvider:	async mkdir(resource: URI): Promise<void> {
		try {
			const parent = await this.getDirectoryHandle(this.extUri.dirname(resource));
			if (!parent) {
				throw this.createFileSystemProviderError(resource, 'No such parent directory, mkdir', FileSystemProviderErrorCode.FileNotFound);
			}

			await parent.getDirectoryHandle(this.extUri.basename(resource), { create: true });
		} catch (error) {
			throw this.toFileSystemProviderError(error);
		}
	}