docs: public MemcachedNode getPrimary(String k) {
          if (partialStringHash.get()) {
              final int index = k.indexOf(hashDelimiter.get());
              if (index > 0) {
                  k = k.substring(0, index);
              }
          }
  
          final long _hash = hashingAlgorithm.hash(k);
          Long hash = Long.valueOf(_hash);
          hash = ketamaNodes.ceilingKey(hash);
          if (hash == null) {
              hash = ketamaNodes.firstKey();
          }
          return ketamaNodes.get(hash);
      }