dumb iterator implemented ith faster hashmap

Cargo.lock

@@ -954,6 +954,12 @@ version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "adad44e29e4c806119491a7f06f03de4d1af22c3a680dd47f1e6e179439d1f56"
 
+[[package]]
+name = "rustc-hash"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "583034fd73374156e66797ed8e5b0d5690409c9226b22d87cb7f19821c05d152"
+
 [[package]]
 name = "rustix"
 version = "0.38.32"
@@ -1218,6 +1224,7 @@ dependencies = [
  "png",
  "pretty_env_logger",
  "rand",
+ "rustc-hash",
  "serde",
  "thiserror",
  "tobj",