public NonceKey createNonceKey(final long nonceGroup, final long nonce) {
    return (nonce == HConstants.NO_NONCE) ? null : new NonceKey(nonceGroup, nonce);
  }
Create a NonceKey from the specified nonceGroup and nonce.
@param nonceGroup the group to use for the {@link NonceKey}
@param nonce      the nonce to use in the {@link NonceKey}
@return the generated NonceKey
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java