-- test ht
-+ optimize tracing code, still too much overhead
-+ use NULL instead of a sentinal node in skiplist and list
-- make interfaces for all data structures consistent
-+ make list and skiplist use string keys
-- optimize integer keys
+- txn write after write can just update the old update record instead of pushing a new one
+- use a shared scan for write-set validation in txn, similar to ht copy logic
+- experiment with the performance impact of not passing the hash between functions in ht
+- experiment with embedding the nstring keys in the list/skiplist nodes
+- lower skiplist's high_water when the actual number of levels in use drops
+- non-power-of 2 sized hashtables for improved memory usage
+- mem2
+
+features
+--------
+- allow values of 0 to be inserted into maps (change DOES_NOT_EXIST to something other than 0)
+- read-committed type transactions
+- recycle free regions across size-classes and between threads