public int numLeafKeysIssued(){
  lock.lock();
  try {
    return issuedExternalKeys + issuedInternalKeys;
  }
  finally {
    lock.unlock();
  }
}

public int numLeafKeysIssued ( ) { lock . lock ( ) ; try { return issuedExternalKeys + issuedInternalKeys ; } finally { lock . unlock ( ) ; } }
returns number of leaf keys used including both internal and external paths . this may be fewer than the number that have been deserialized or held in memory , because of the lookahead zone .
