public Object[] toArrayHelper(int offset) {
        final int N = colGetSize();
        Object[] result = new Object[N];
        for (int i = 0; i < N; i++) {
            result[i] = colGetEntry(i, offset);
        }
        return result;
    }
Helper for writing standard Java collection interfaces to a data
structure like {@link ArrayMap}.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/collection/MapCollections.java