protected String getServiceConfig(final List<ServiceInstance> instances) {
        for (final ServiceInstance inst : instances) {
            final Map<String, String> metadata = inst.getMetadata();
            if (metadata == null || metadata.isEmpty()) {
                continue;
            }
            final String metaValue = metadata.get(CLOUD_DISCOVERY_METADATA_SERVICE_CONFIG);
            if (metaValue != null && !metaValue.isEmpty()) {
                return metaValue;
            }
        }
        return null;
    }
Extracts the gRPC service config string from the given service instances.

@param instances The list of instances to extract the service config from.
@return The gRPC service config or null.
grpc-client-spring-boot-starter/src/main/java/net/devh/boot/grpc/client/nameresolver/DiscoveryClientNameResolver.java