docs: @Override
      public void removeNeighbor(final TrustGraphNodeId neighbor) {
          // all modification operations are serialized
          synchronized(this) {
              // do nothing if there is no entry for the neighbor specified
              if (!contains(neighbor)) {
                  return;
              }
  
              /* first remove the neighbor from the ordering. This will 
               * prevent it from being advertised to.
               */
              removeNeighborFromOrdering(neighbor);
              removeNeighborFromRoutingTable(neighbor);
          }
      }