default Map<String, ConnectivityState> getConnectivityState() {
        return Collections.emptyMap();
    }
Gets an unmodifiable map that contains the names of the created channel with their current
{@link ConnectivityState}. This method will return an empty map, if the feature is not supported.

@return A map with the channel names and their connectivity state.
grpc-client-spring-boot-starter/src/main/java/net/devh/boot/grpc/client/channelfactory/GrpcChannelFactory.java