src/vs/workbench/api/browser/mainThreadTunnelService.ts/MainThreadTunnelService/$openTunnel
class MainThreadTunnelService:	async $openTunnel(tunnelOptions: TunnelOptions, source: string): Promise<TunnelDto | undefined> {
		const tunnel = await this.remoteExplorerService.forward({
			remote: tunnelOptions.remoteAddress,
			local: tunnelOptions.localAddressPort,
			name: tunnelOptions.label,
			source: {
				source: TunnelSource.Extension,
				description: source
			},
			elevateIfNeeded: false
		});
		if (tunnel) {
			if (!this.elevateionRetry
				&& (tunnelOptions.localAddressPort !== undefined)
				&& (tunnel.tunnelLocalPort !== undefined)
				&& isPortPrivileged(tunnelOptions.localAddressPort)
				&& (tunnel.tunnelLocalPort !== tunnelOptions.localAddressPort)
				&& this.tunnelService.canElevate) {

				this.elevationPrompt(tunnelOptions, tunnel, source);
			}
			return TunnelDto.fromServiceTunnel(tunnel);
		}
		return undefined;
	}