Merge pull request #12112 from nextcloud/backport/12038/stable13

[13] Implement the size of an assembly stream

Author: MorrisJobke

apps/dav/lib/Upload/AssemblyStream.php

@@ -161,7 +161,9 @@ public function stream_truncate($size) {
 	 * @return array
 	 */
 	public function stream_stat() {
-		return [];
+		return [
+			'size' => $this->size,
+		];
 	}
 
 	/**