Async function to fetch LPLinkMetadata

LPLinkMetadata+FetchingAsync.swift

import LinkPresentation

extension LPLinkMetadata {
    static func fetching(for url: URL) async throws -> LPLinkMetadata {
        let provider = LPMetadataProvider()
        return try await withTaskCancellationHandler {
            try await withCheckedThrowingContinuation { continuation in
                provider.startFetchingMetadata(for: url) { metadata, error in
                    switch (metadata, error) {
                    case (nil, let error?):
                        continuation.resume(throwing: error)
                    case (let output?, nil):
                        continuation.resume(returning: output)
                    case (_?, _?):
                        preconditionFailure("Expected nil metadata or nil error, but both were some")
                    case (nil, nil):
                        preconditionFailure("Expected some metadata or some error, but both were nil")
                    }
                }
            }
        } onCancel: {
            provider.cancel()
        }
    }
}

Huh, the discussion comment here suggests that startFetchingMetadata is usable as async out of the box, so probably don't use this gist