src/vs/platform/files/common/inMemoryFilesystemProvider.ts/InMemoryFileSystemProvider/setReadOnly
class InMemoryFileSystemProvider:	setReadOnly(readonly: boolean) {
		const isReadonly = !!(this._capabilities & FileSystemProviderCapabilities.Readonly);
		if (readonly !== isReadonly) {
			this._capabilities = readonly ? FileSystemProviderCapabilities.Readonly | FileSystemProviderCapabilities.PathCaseSensitive | FileSystemProviderCapabilities.FileReadWrite
				: FileSystemProviderCapabilities.FileReadWrite | FileSystemProviderCapabilities.PathCaseSensitive;
			this._onDidChangeCapabilities.fire();
		}
	}