extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts/BufferSyncSupport/onDidChangeTextDocument
class BufferSyncSupport:	private onDidChangeTextDocument(e: vscode.TextDocumentChangeEvent): void {
		const syncedBuffer = this.syncedBuffers.get(e.document.uri);
		if (!syncedBuffer) {
			return;
		}

		this._onWillChange.fire(syncedBuffer.resource);

		syncedBuffer.onContentChanged(e.contentChanges);
		const didTrigger = this.requestDiagnostic(syncedBuffer);

		if (!didTrigger && this.pendingGetErr) {
			// In this case we always want to re-trigger all diagnostics
			this.pendingGetErr.cancel();
			this.pendingGetErr = undefined;
			this.triggerDiagnostics();
		}
	}