static GrantorInfo becomeGrantor(DLockService service, int dlsSerialNumber,
      InternalDistributedMember oldTurk, InternalDistributedSystem sys) {
    return basicOp(-1, service, dlsSerialNumber, sys, oldTurk, BECOME_OP);
  }
Tells the elder we want to become the grantor

@param service the service we want to be the grantor of.
@param oldTurk if non-null then only become grantor if it is currently oldTurk.
@param sys the distributed system
@return information describing the previous grantor, if any, and if we need to do a grantor
        recovery
geode-core/src/main/java/org/apache/geode/distributed/internal/locks/GrantorRequestProcessor.java