code: public boolean addGrant(
        ClusterNode node, String sessionId, ResourceRequestInfo req) {
      synchronized (node) {
        if (node.deleted) {
          return false;
        }
        if (!node.checkForGrant(Utilities.getUnitResourceRequest(
          req.getType()), resourceLimit)) {
          return false;
        }
  
        node.addGrant(sessionId, req);
        loadManager.incrementLoad(req.getType());
        hostsToSessions.get(node).add(sessionId);
        if (!node.checkForGrant(Utilities.getUnitResourceRequest(
          req.getType()), resourceLimit)) {
          RunnableIndices r = typeToIndices.get(req.getType());
          r.deleteRunnable(node);
        }
      }
      return true;
    }
docs: Add a grant to a node
  @param node the node the grant is on
  @param sessionId the session the grant is given to
  @param req the request this grant satisfies
  @return true if the grant can be added to the node, false otherwise