src/vs/workbench/services/extensions/electron-sandbox/localProcessExtensionHost.ts/SandboxLocalProcessExtensionHost/start
class SandboxLocalProcessExtensionHost:	public start(): Promise<IMessagePassingProtocol> {
		if (this._terminating) {
			// .terminate() was called
			throw new CancellationError();
		}

		if (!this._messageProtocol) {
			this._messageProtocol = this._start();
		}

		return this._messageProtocol;
	}