src/vs/server/node/remoteExtensionHostAgentServer.ts/RemoteExtensionHostAgentServer/_updateWithFreeDebugPort
class RemoteExtensionHostAgentServer:	private _updateWithFreeDebugPort(startParams: IRemoteExtensionHostStartParams): Thenable<IRemoteExtensionHostStartParams> {
		if (typeof startParams.port === 'number') {
			return findFreePort(startParams.port, 10 /* try 10 ports */, 5000 /* try up to 5 seconds */).then(freePort => {
				startParams.port = freePort;
				return startParams;
			});
		}
		// No port clear debug configuration.
		startParams.debugId = undefined;
		startParams.port = undefined;
		startParams.break = undefined;
		return Promise.resolve(startParams);
	}