extensions/typescript-language-features/src/languageFeatures/diagnostics.ts/DiagnosticsManager/scheduleDiagnosticsUpdate
class DiagnosticsManager:	private scheduleDiagnosticsUpdate(file: vscode.Uri) {
		if (!this._pendingUpdates.has(file)) {
			this._pendingUpdates.set(file, setTimeout(() => this.updateCurrentDiagnostics(file), this._updateDelay));
		}
	}