That eventually pulls things like once_cell that require atomics on some platforms (compare-exchange), and in general HashMap is quite heavy primitive that is still not in alloc of Rust itself

Full hashbrown is pulled in

• algebra/ec/src/scalar_mul/variable_base/stream_pippenger.rs

  Line 5 in bb663bc

  use hashbrown::HashMap;

  - for peppinger - can be solved by feature gate. Independently, do you think unordered map wins here performance-wise vs ordered (a-la BTree)?

• algebra/ec/src/hashing/curve_maps/swu.rs

  Line 154 in bb663bc

  use hashbrown::HashMap;

  - in test, dev-dependencies will just work

• algebra/ec/src/hashing/curve_maps/elligator2.rs

  Line 161 in bb663bc

  use hashbrown::HashMap;

  - same, tests only