aws-s3(-multipart): add new options

docs/uploader/aws-s3-multipart.mdx

@@ -390,4 +390,20 @@ or between `500` and `600`.
 
 </details>
 
+#### `shouldUseMultipart(file, fileSize)`
+
+A function that returns a boolean, or a boolean value. If a function is
+provided, the following arguments will be provided:
+
+- `file` - the `UppyFile` object.
+- `fileSize` – the number of bytes to upload.
+
+By default, all files are uploaded as multipart. In a future version, all files
+with a size ≤ 100 MiB will be uploaded in a single chunk, all files larger than
+that as multipart.
+
+#### `getUploadParameters(file)`
+
+See [`@uppy/aws-s3`][]. This option is used only for non-multipart uploads.
+
 [`@uppy/aws-s3`]: /docs/aws-s3

docs/uploader/aws-s3.mdx

@@ -315,6 +315,20 @@ upload as query parameters (`Array`, default: `null`).
 - Set this to `null` (the default) to send _all_ metadata fields.
 - Set this to an empty array `[]` to not send any fields.
 
+#### `shouldUseMultipart(file, fileSize)`
+
+When provided, this plugin will be swaped with [`@uppy/aws-s3-multipart`][].
+
+A function that returns a boolean, or a boolean value. If a function is
+provided, the following arguments will be provided:
+
+- `file` - the `UppyFile` object.
+- `fileSize` – the number of bytes to upload.
+
+By default, all files are uploaded as a single chunk. In a future version, all
+files with a size ≤ 100 MiB will be uploaded in a single chunk, all files larger
+than that as multipart.
+
 #### `getUploadParameters(file)`
 
 :::note
@@ -448,4 +462,5 @@ uppy.on('upload-success', (file, data) => {
 });
 ```
 
+[`@uppy/aws-s3-multipart`]: /docs/aws-s3-multipart
 [companion docs]: /docs/companion