void setIntUnchecked(final int index, final int value) {
        Holder.unsafe.putInt(this.base, this.address + index, value);
    }
Sets the specified 32-bit integer at the specified absolute
{@code index} in this buffer.

@throws IndexOutOfBoundsException if the specified {@code index} is less than {@code 0} or
{@code index + 4} is greater than {@code this.length()}
embulk-core/src/main/java/org/embulk/exec/Slice.java