switch transport {
		case istionetworking.TransportProtocolTCP:
			transportSocket = buildDownstreamTLSTransportSocket(chain.tlsContext)
		case istionetworking.TransportProtocolQUIC:
			transportSocket = buildDownstreamQUICTransportSocket(chain.tlsContext)
		}
		filterChains = append(filterChains, &listener.FilterChain{
			FilterChainMatch: match,
			TransportSocket:  transportSocket,
		})
	}