* @param entry the entry
* @return the entry size, or {@code null} if segment has no space
*/
- <T> @Nullable Integer append(final ByteBufMapper<T> mapper, final T entry) {
+ <T> @Nullable Integer append(final ToByteBufMapper<T> mapper, final T entry) {
// we are appending at this index and position
final long index = nextIndex();
final int position = currentPosition;