questions asscociated with iterators in starter project

[ppdogg]

1. Is there some rules about names? In MergeIterator you use create, but in LsmIterator and FusedIterator you use new.
2. Is there some rules about returning a type or result? LsmIterator::new() returns Result<Self>, but MergeIterator::create() and FusedIterator::new() return Self.
3. I implement a new range iterator that accepts Range like 1..10 rather than (Bound, Bound). I have to add new struct in mem_table.rs and lsm_iterators.rs.
   In mem_table.rs, crossbeam_skiplist::map::Range<'this, Bytes, Range<Bytes>, Bytes, Bytes> to replace old SkipMapRangeIter<'this>.
   In lsm_iterators.rs, you specify MergeIterator<MemTableIterator> rather than use generic. That's why I have to add new duplicated code.
   Is there any reasons why you don't use generic? Is there any better ways to add a range iterator?

[ppdogg]

Will you consider changing SkipMapRangeIter definition? This would be compatible with adding range iterator for memtable.

type SkipMapRangeIter<'a, Q, R>
= crossbeam_skiplist::map::Range<'a, Q, R, Bytes, Bytes>;

Example:
iter: SkipMapRangeIter<'this, Bytes, (Bound<Bytes>, Bound<Bytes>)>,
and
iter: SkipMapRangeIter<'this, Bytes, Range<Bytes>>,