Update port attributes api to not use array

Par of #115616

src/vs/vscode.proposed.d.ts

@@ -2888,11 +2888,11 @@ declare module 'vscode' {
 
 	export interface PortAttributesProvider {
 		/**
-		 * Provides attributes for the given ports. For ports that your extension doesn't know about, simply don't include
-		 * them in the returned array. For example, if `providePortAttributes` is called with ports [3000, 4000] but your
-		 * extension doesn't know anything about those ports you can return an empty array.
+		 * Provides attributes for the given port. For ports that your extension doesn't know about, simply
+		 * return undefined. For example, if `providePortAttributes` is called with ports 3000 but your
+		 * extension doesn't know anything about 3000 you should return undefined.
 		 */
-		providePortAttributes(ports: number[], pid: number | undefined, commandLine: string | undefined, token: CancellationToken): ProviderResult<PortAttributes[]>;
+		providePortAttributes(port: number, pid: number | undefined, commandLine: string | undefined, token: CancellationToken): ProviderResult<PortAttributes>;
 	}
 
 	export namespace workspace {

src/vs/workbench/api/node/extHostTunnelService.ts

@@ -22,7 +22,6 @@ import { IExtensionDescription } from 'vs/platform/extensions/common/extensions'
 import { MovingAverage } from 'vs/base/common/numbers';
 import { CandidatePort } from 'vs/workbench/services/remote/common/remoteExplorerService';
 import { ILogService } from 'vs/platform/log/common/log';
-import { flatten } from 'vs/base/common/arrays';
 
 class ExtensionTunnel implements vscode.Tunnel {
 	private _onDispose: Emitter<void> = new Emitter();
@@ -240,17 +239,20 @@ export class ExtHostTunnelService extends Disposable implements IExtHostTunnelSe
 	}
 
 	async $providePortAttributes(handles: number[], ports: number[], pid: number | undefined, commandline: string | undefined, cancellationToken: vscode.CancellationToken): Promise<ProvidedPortAttributes[]> {
-		const providedAttributes = await Promise.all(handles.map(handle => {
+		const providedAttributes: vscode.ProviderResult<vscode.PortAttributes>[] = [];
+		for (const handle of handles) {
 			const provider = this._portAttributesProviders.get(handle);
 			if (!provider) {
 				return [];
 			}
-			return provider.provider.providePortAttributes(ports, pid, commandline, cancellationToken);
-		}));
+			providedAttributes.push(...(await Promise.all(ports.map(async (port) => {
+				return provider.provider.providePortAttributes(port, pid, commandline, cancellationToken);
+			}))));
+		}
 
-		const allAttributes = <vscode.PortAttributes[][]>providedAttributes.filter(attribute => !!attribute && attribute.length > 0);
+		const allAttributes = <vscode.PortAttributes[]>providedAttributes.filter(attribute => !!attribute);
 
-		return (allAttributes.length > 0) ? flatten(allAttributes).map(attributes => {
+		return (allAttributes.length > 0) ? allAttributes.map(attributes => {
 			return {
 				autoForwardAction: <ProvidedOnAutoForward><unknown>attributes.autoForwardAction,
 				port: attributes.port