高速なHasherを使う (SipHashのかわりに) #156
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## 変更内容 ### #153 #### 仮のTransformerで「とりあえず」の全頂点の変換処理を行う - x-y 入れかえ処理を入れておく - これにともない GeoJSON, GeoPackage ドライバ内での x-y 入れかえは除去する - CRSを WGS 84 にしておく処理も追加 #155 #### Gpkg, GeoJSON 周りのリファクタリング - `nusamai-geojson` に "indexed" でないふつうのジオメトリをGeoJSON Valueに変換する関数を追加（tiling2d sink で使う）。 - #154 もこのPRにマージ - Gpkg のバイナリジオメトリの構築で、 `Vec<u8>` でなく `std::io::Write` trait を使う（`Vec<u8>`はWrite）。一時的なVecの生成も除去。 ### その他 - Gpkg sink が、インメモリSQLiteを扱えていない（`:memory:` というファイルを作ってしまう）問題を修正 - SipHash → aHash #156 - Iterator::chain 除去 #157 - Noop Sink, Serde Sinkを走らせるだけのテストに GeoJSONとGPKG も追加 - `nusamai_citygml::object::Geometries` の名前を `GeometryStore` に変更（ジオメトリのつめあわせであることを多少分かりやすく） - `GeometryStore` にCRSの情報をもたせられるようにしておく（仮） - その他細かい調整など
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HashMap, IndexMap, etc. を多用する場面で、 Hasher を ahash に切り替える。
背景
Rust の HashMap / HashSet はデフォルトで SipHash-1-3 (
std::hash::SipHash) というハッシュ関数を使う。SipHashはHashDos攻撃への耐性が高いためにデフォルトのHasherとして採用されている。しかし高い HashDos 耐性が必要なく、hashを多用する場面ではより軽量なHasherに切り替えることができる（切り替えることがしばしば行われる）。