A wrapper around iOS Entity/loadAsync(named:in:) and visionOS Entity(named:in:) async that works on both platforms

TextureResource+LoadFileAsync.swift

//
//  TextureResource+LoadFileAsync.swift
//
//  Created by Drew Olbrich on 12/24/23.
//  Copyright © 2023 Lunar Skydiving LLC. All rights reserved.
//
//  MIT License
//  
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//  
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//  
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

import Foundation
import RealityKit
import Combine

extension TextureResource {
    
    // The RealityKit visionOS `TextureResource(named:in:options:) async` initializer
    // isn't available in iOS 17, so we implement our own replacement on iOS and wrap
    // both implementations in `TextureResource/loadFileAsync(named:in:options:)`.
    
#if os(visionOS)
    
    /// Loads a texture resource from a file in a bundle asynchronously.
    ///
    /// Unlike `TextureResource(named:in:options:) async` or
    /// `TextureResource.loadAsync(named:in:options:)`, this method  works on both iOS
    /// and visionOS.
    static func loadFileAsync(named name: String, in bundle: Bundle? = nil, options: TextureResource.CreateOptions = .init(semantic: nil)) async throws -> TextureResource {
        return try await TextureResource(named: name, in: bundle, options: options)
    }
    
#else // !os(visionOS)
    
    /// Loads a texture resource from a file in a bundle asynchronously.
    ///
    /// Unlike `TextureResource(named:in:options:) async` or
    /// `TextureResource.loadAsync(named:in:options:)`, this method  works on both iOS
    /// and visionOS.
    static func loadFileAsync(named name: String, in bundle: Bundle? = nil, options: TextureResource.CreateOptions = .init(semantic: nil)) async throws -> TextureResource {
        return try await withCheckedThrowingContinuation { continuation in
            var cancellable: AnyCancellable?
            cancellable = TextureResource.loadAsync(named: name, in: bundle, options: options).sink(receiveCompletion: { completion in
                switch completion {
                case .finished:
                    break
                case .failure(let error):
                    continuation.resume(throwing: error)
                }
                cancellable?.cancel()
            }, receiveValue: { entity in
                continuation.resume(returning: entity)
                cancellable?.cancel()
            })
        }
    }
    
#endif // !os(visionOS)
    
}