diff --git a/Modules/RSWeb/Sources/RSWeb/Downloader.swift b/Modules/RSWeb/Sources/RSWeb/Downloader.swift
index f82638246..b8362e07e 100755
--- a/Modules/RSWeb/Sources/RSWeb/Downloader.swift
+++ b/Modules/RSWeb/Sources/RSWeb/Downloader.swift
@@ -23,7 +23,6 @@ public typealias DownloadCallback = @MainActor (Data?, URLResponse?, Error?) ->
 	private static let debugLoggingEnabled = true
 
 	private init() {
-
 		let sessionConfiguration = URLSessionConfiguration.ephemeral
 		sessionConfiguration.requestCachePolicy = .reloadIgnoringLocalCacheData
 		sessionConfiguration.httpShouldSetCookies = false
@@ -54,50 +53,65 @@ public typealias DownloadCallback = @MainActor (Data?, URLResponse?, Error?) ->
 			return
 		}
 
-		if callbacks[url] == nil {
-			if Self.debugLoggingEnabled {
-				Self.logger.debug("Downloader: downloading \(url)")
-			}
-			callbacks[url] = [completion]
-		} else {
-			// A download is already be in progress for this URL. Don’t start a separate download.
-			// Add the callback to the callbacks array for this URL.
-			if Self.debugLoggingEnabled {
-				Self.logger.debug("Downloader: download in progress for \(url) — adding callback")
-			}
-			callbacks[url]?.append(completion)
-			return
-		}
+		addCallback(url: url, callback: completion)
 
 		var urlRequestToUse = urlRequest
 		urlRequestToUse.addSpecialCaseUserAgentIfNeeded()
 
 		let task = urlSession.dataTask(with: urlRequestToUse) { (data, response, error) in
 			Task { @MainActor in
-				let callbacksForURL = self.callbacks[url]
-				assert(callbacksForURL != nil)
-
-				if let callbacksForURL {
-					if Self.debugLoggingEnabled {
-						let count = callbacksForURL.count
-						if count == 1 {
-							Self.logger.debug("Downloader: calling 1 callback for URL \(url)")
-						} else {
-							Self.logger.debug("Downloader: calling \(callbacksForURL.count) callbacks for URL \(url)")
-						}
-					}
-
-					for completion in callbacksForURL {
-						completion(data, response, error)
-					}
-				} else {
-					assertionFailure("Downloader: downloaded URL \(url) but no callbacks found")
-					Self.logger.fault("Downloader: downloaded URL \(url) but no callbacks found")
-				}
-
-				self.callbacks[url] = nil
+				self.callAndReleaseCallbacks(url, data, response, error)
 			}
 		}
 		task.resume()
 	}
 }
+
+private extension Downloader {
+
+	func addCallback(url: URL, callback: @escaping DownloadCallback) {
+		assert(Thread.isMainThread)
+
+		if callbacks[url] == nil {
+			if Self.debugLoggingEnabled {
+				Self.logger.debug("Downloader: downloading \(url)")
+			}
+			callbacks[url] = [callback]
+		} else {
+			// A download is already be in progress for this URL. Don’t start a separate download.
+			// Add the callback to the callbacks array for this URL.
+			if Self.debugLoggingEnabled {
+				Self.logger.debug("Downloader: download in progress for \(url) — adding callback")
+			}
+			callbacks[url]?.append(callback)
+			return
+		}
+	}
+
+	func callAndReleaseCallbacks(_ url: URL, _ data: Data? = nil, _ response: URLResponse? = nil, _ error: Error? = nil) {
+		assert(Thread.isMainThread)
+
+		defer {
+			callbacks[url] = nil
+		}
+
+		guard let callbacksForURL = callbacks[url] else {
+			assertionFailure("Downloader: downloaded URL \(url) but no callbacks found")
+			Self.logger.fault("Downloader: downloaded URL \(url) but no callbacks found")
+			return
+		}
+
+		if Self.debugLoggingEnabled {
+			let count = callbacksForURL.count
+			if count == 1 {
+				Self.logger.debug("Downloader: calling 1 callback for URL \(url)")
+			} else {
+				Self.logger.debug("Downloader: calling \(count) callbacks for URL \(url)")
+			}
+		}
+
+		for callback in callbacksForURL {
+			callback(data, response, error)
+		}
+	}
+}