src/vs/platform/tunnel/common/tunnel.ts/AbstractTunnelService/getExistingTunnel
class AbstractTunnelService:	async getExistingTunnel(remoteHost: string, remotePort: number): Promise<RemoteTunnel | undefined> {
		if (isAllInterfaces(remoteHost) || isLocalhost(remoteHost)) {
			remoteHost = LOCALHOST_ADDRESSES[0];
		}

		const existing = this.getTunnelFromMap(remoteHost, remotePort);
		if (existing) {
			++existing.refcount;
			return existing.value;
		}
		return undefined;
	}