The code of Method publishConfig of Class ConsulDynamicConfiguration:
```java
    @Override
    public boolean publishConfig(String key, String group, String content) throws UnsupportedOperationException {
        String normalizedKey = convertKey(group, key);
        return kvClient.putValue(normalizedKey + PATH_SEPARATOR + content);
    }
```
We want put a config with value with the "content", but the method just add the "content" to the key and put a null value.
import org.apache.dubbo.common.config.configcenter.ConfigChangeType;
import org.apache.dubbo.common.config.configcenter.ConfigChangedEvent;
import org.apache.dubbo.common.config.configcenter.ConfigurationListener;
import org.apache.dubbo.common.config.configcenter.DynamicConfiguration;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.StringUtils;
import com.google.common.base.Charsets;
import com.google.common.net.HostAndPort;
import com.orbitz.consul.Consul;
import com.orbitz.consul.KeyValueClient;
import com.orbitz.consul.cache.KVCache;
import com.orbitz.consul.model.kv.Value;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import static org.apache.dubbo.common.config.configcenter.Constants.CONFIG_NAMESPACE_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.PATH_SEPARATOR;
import static org.apache.dubbo.common.utils.StringUtils.EMPTY_STRING;
/**
 * config center implementation for consul
 */
public class ConsulDynamicConfiguration implements DynamicConfiguration {