src/vs/workbench/api/common/extHostDiagnostics.ts/DiagnosticCollection/dispose
class DiagnosticCollection:	dispose(): void {
		if (!this._isDisposed) {
			this._onDidChangeDiagnostics.fire([...this._data.keys()]);
			if (this._proxy) {
				this._proxy.$clear(this._owner);
			}
			this._data = undefined!;
			this._isDisposed = true;
		}
	}