make headers editable

Author: itisnajim

lib/src/functions_client.dart

@@ -13,6 +13,26 @@ class FunctionsClient {
   final YAJsonIsolate _isolate;
   final bool _hasCustomIsolate;
 
+  /// Getter for the headers
+  Map<String, String> get headers {
+    return _headers;
+  }
+
+  /// Sets the headers to be sent with requests.
+  /// If an 'Authorization' header is already present,
+  /// it will be kept unless removeAuth is called first.
+  /// @param value a Map containing the new headers to set.
+  set headers(Map<String, String> value) {
+    final authHeader =
+        _headers['Authorization']; // Get the existing Authorization header
+
+    _headers
+      ..clear()
+      ..addAll(Constants.defaultHeaders)
+      ..addAll(authHeader == null ? {} : {'Authorization': authHeader})
+      ..addAll(value);
+  }
+
   /// In case you don't provide your own isolate, call [dispose] when you're done
   FunctionsClient(
     String url,
@@ -32,6 +52,14 @@ class FunctionsClient {
     _headers['Authorization'] = 'Bearer $token';
   }
 
+  /// Removes the Authorization header from the headers map, if it exists.
+  ///
+  /// Returns the token value that was removed from the header,
+  /// without the 'Bearer ' prefix, or null if the header was not present.
+  String? removeAuth() {
+    return _headers.remove('Authorization')?.replaceFirst('Bearer ', '');
+  }
+
   /// Invokes a function
   ///
   /// [functionName] - the name of the function to invoke