> sensible choice is made for you At the moment, it's chosen to be 6: https://doc.rust-lang.org/src/collections/btree/map.rs.html#156 https://doc.rust-lang.org

> sensible choice is made for you At the moment, it's chosen to be 6: https://doc.rust-lang.org/src/collections/btree/map.rs.html#156 https://doc.rust-lang.org/src/collections/btree/map.rs.html#... (note the FIXME though).