code: protected ClientTransport remove(ProviderInfo providerInfo) {
          providerLock.lock();
          try {
              ClientTransport transport = uninitializedConnections.remove(providerInfo);
              if (transport == null) {
                  transport = aliveConnections.remove(providerInfo);
                  if (transport == null) {
                      transport = subHealthConnections.remove(providerInfo);
                      if (transport == null) {
                          transport = retryConnections.remove(providerInfo);
                      }
                  }
              }
              return transport;
          } finally {
              providerLock.unlock();
          }
      }
docs: 删除provider
  
  @param providerInfo the provider
  @return 如果已经建立连接 ，返回ClientTransport