final Object[] baseElements() {
        return elements;
    }
Calculate the capacity we should provision, given the expected size.
<br>
Our capacity must always be a power of 2, and never less than 2 or more
than MAX_CAPACITY.  We use 64-bit numbers here to avoid overflow
concerns.
server-common/src/main/java/org/apache/kafka/timeline/BaseHashTable.java