`downloadFile`: Make type of `begin` required when `progress` is used

[thomasttvo]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used patch-package to patch [email protected] for the project I'm working on.

Related to: https://github.com/itinance/react-native-fs/issues/760

Here is the diff that solved my problem:

diff --git a/node_modules/react-native-fs/index.d.ts b/node_modules/react-native-fs/index.d.ts
index da3fa7d..aa99cd0 100644
--- a/node_modules/react-native-fs/index.d.ts
+++ b/node_modules/react-native-fs/index.d.ts
@@ -41,13 +41,17 @@ type DownloadFileOptions = {
 	cacheable?: boolean // Whether the download can be stored in the shared NSURLCache (iOS only)
 	progressInterval?: number
 	progressDivider?: number
-	begin?: (res: DownloadBeginCallbackResult) => void
-	progress?: (res: DownloadProgressCallbackResult) => void
 	resumable?: () => void // only supported on iOS yet
 	connectionTimeout?: number // only supported on Android yet
 	readTimeout?: number // supported on Android and iOS
 	backgroundTimeout?: number // Maximum time (in milliseconds) to download an entire resource (iOS only, useful for timing out background downloads)
-}
+} & ({
+    begin: (res: DownloadBeginCallbackResult) => void;
+    progress: (res: DownloadProgressCallbackResult) => void;
+	} | {
+    begin?: (res: DownloadBeginCallbackResult) => void;
+    progress?: undefined;
+	})
 	
 type DownloadBeginCallbackResult = {
 	jobId: number // The download job ID, required if one wishes to cancel the download. See `stopDownload`.

This issue body was partially generated by patch-package.