src/vs/workbench/contrib/webviewView/browser/webviewViewService.ts/WebviewViewService/resolve
class WebviewViewService:	resolve(viewType: string, webview: WebviewView, cancellation: CancellationToken): Promise<void> {
		const resolver = this._resolvers.get(viewType);
		if (!resolver) {
			if (this._awaitingRevival.has(viewType)) {
				throw new Error('View already awaiting revival');
			}

			let resolve: () => void;
			const p = new Promise<void>(r => resolve = r);
			this._awaitingRevival.set(viewType, { webview, resolve: resolve! });
			return p;
		}

		return resolver.resolve(webview, cancellation);
	}