public synchronized void setUserBits(byte userBits) {
    long userLong = ((long) userBits) << USER_BITS_SHIFT;// set it as most signifcant byte.

    id &= OPLOG_ID_MASK; // mask the most significant byte in id.
    id |= userLong; // set the most significant byte in id.

    // Assert.assertTrue(userBit == getUserBits());
  }
@param userBits The userBit to set.
geode-core/src/main/java/org/apache/geode/internal/cache/DiskId.java