feat(dynamite_runtime,nextcloud): add addAll method to HttpHeaders

packages/dynamite/dynamite_runtime/lib/src/dynamite_client.dart

@@ -442,9 +442,8 @@ class DynamiteClient {
     final Set<int>? validStatuses,
   ) async {
     final request = await httpClient.openUrl(method, uri);
-    for (final header in headers.entries) {
-      request.headers.add(header.key, header.value);
-    }
+    request.headers.addAll(headers);
+
     if (body != null) {
       request.add(body);
     }

packages/dynamite/dynamite_runtime/lib/src/http_extensions.dart

@@ -41,3 +41,13 @@ extension HttpClientResponseExtension on HttpClientResponse {
     return responseHeaders;
   }
 }
+
+/// Extension for http headers.
+extension HttpHeadersExtension on HttpHeaders {
+  /// Iteratively adds all header values.
+  void addAll(final Map<String, String> headers) {
+    for (final header in headers.entries) {
+      add(header.key, header.value);
+    }
+  }
+}

packages/nextcloud/lib/src/webdav/client.dart

@@ -32,14 +32,13 @@ class WebDavClient {
 
     final request = await rootClient.httpClient.openUrl(method, url)
       ..persistentConnection = true;
-    for (final header in {
+
+    request.headers.addAll({
       HttpHeaders.contentTypeHeader: 'application/xml',
       ...?rootClient.baseHeaders,
       ...?headers,
       ...?rootClient.authentications.firstOrNull?.headers,
-    }.entries) {
-      request.headers.add(header.key, header.value);
-    }
+    });
 
     if (data != null) {
       request.add(data);