code: public CompletableFuture<Collection<InetSocketAddress>> getRpcNodeAddresses(final Serializable userid) {
          if (this.sncpNodeAddresses != null) {
              tryAcquireSemaphore();
              CompletableFuture<Collection<InetSocketAddress>> result = this.sncpNodeAddresses.getCollectionAsync(SOURCE_SNCP_USERID_PREFIX + userid, InetSocketAddress.class);
              if (semaphore != null) result.whenComplete((r, e) -> releaseSemaphore());
              return result;
          }
          List<InetSocketAddress> rs = new ArrayList<>();
          rs.add(this.localSncpAddress);
          return CompletableFuture.completedFuture(rs);
      }
docs: 获取用户在线的SNCP节点地址列表，不是分布式则返回元素数量为1，且元素值为null的列表<br>
  InetSocketAddress 为 SNCP节点地址
  
  @param userid Serializable
  
  @return 地址列表