Sample Code for ModelActor

Database.swift

public protocol Database: Sendable {
  func delete<T: PersistentModel>(
    where predicate: Predicate<T>?
  ) async throws

  func insert(_ closuer: @Sendable @escaping () -> some PersistentModel) async

  func fetch<T, U : Sendable>(
    _ selectDescriptor: @escaping @Sendable () -> FetchDescriptor<T>,
    with closure: @escaping @Sendable ([T]) throws -> U
  ) async throws -> U

   func fetch<T,  U : Sendable>(
    for objectID: PersistentIdentifier,
    with closure: @escaping @Sendable (T?) throws -> U
  ) async throws -> U? where T: PersistentModel

  func transaction(_ block: @Sendable @escaping (ModelContext) throws -> Void) async throws
}

extension Database {
  public static var loggingCategory: BushelLogging.Category {
    .data
  }

  public func deleteAll(of types: [any PersistentModel.Type]) async throws {
    try await self.transaction { context in
      try types.forEach {
        try context.delete(model: $0)
      }
    }
  }

  public func delete<T: PersistentModel>(
    model _: T.Type,
    where predicate: Predicate<T>? = nil
  ) async throws {
    try await self.delete(where: predicate)
  }

  func fetch<T,  U : Sendable>(
    _ modelID: ModelID<T>,
   with closure: @escaping @Sendable (T?) throws -> U
  ) async throws -> U? where T: PersistentModel {
    try await self.fetch(for: modelID.persistentIdentifier, with: closure)
  }
}