private static int capacity(int expectedSize) {
        if (expectedSize < 3) {
            Requires.requireTrue(expectedSize >= 0, "expectedSize cannot be negative but was: " + expectedSize);
            return expectedSize + 1;
        }
        if (expectedSize < Ints.MAX_POWER_OF_TWO) {
            return expectedSize + expectedSize / 3;
        }
        return Integer.MAX_VALUE; // any large value
    }
Returns a capacity that is sufficient to keep the map from being resized as
long as it grows no larger than expectedSize and the load factor is >= its
default (0.75).
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/util/Maps.java