Could apiHash be computed as an unordered hash of the name hashes?

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val apiHash: HashAPI.Hash = HashAPI(classApi)
    val nameHashes = (new xsbt.api.NameHashing(options.useOptimizedSealed())).nameHashes(classApi)
    classApi.definitionType match {
      case d @ (DefinitionType.ClassDef | DefinitionType.Trait) =>
        val extraApiHash = {
          if (d != DefinitionType.Trait) apiHash
          else HashAPI(_.hashAPI(classApi), includePrivateDefsInTrait = true)
        }

        classApis(className) = ApiInfo(apiHash, extraApiHash, savedClassApi)
        classPublicNameHashes(className) = nameHashes.toArray
      case DefinitionType.Module | DefinitionType.PackageModule =>
        objectApis(className) = ApiInfo(apiHash, apiHash, savedClassApi)
        objectPublicNameHashes(className) = nameHashes.toArray

Now that name hashing is aways enabled, could we just redefine apiHash as f(nameHashes)? This would save about 10% of of the work in extract-api phase.

[retronym]

Another implementation strategy would be to change hashDefinition to cache its result on the Definition that it hashes, so the subesquent call will avoid the work.

[retronym]