make TestStream use a cursor when reading instead of popping from the front
make TestStream use a cursor when reading instead of popping from the front

numerodix/memcache.rs,numerodix/memcache.rs,numerodix/memcache.rs,numerodix/emcache,numerodix/memcache.rs,numerodix/emcache,numerodix/emcache,numerodix/emcache