error tests expansion

Railway/ResultExtensions.cs

@@ -98,7 +98,7 @@ public static partial class ResultExtensions
                 case ResultState.Success:
                     if (hasErrors) goto afterLoop;
                     break;
-                    
+
                 default: throw new ResultNotInitializedException(nameof(results));
             }
         }
@@ -145,7 +145,19 @@ public static partial class ResultExtensions
     }
     public static async Task<Result<IEnumerable<T>>> Merge<T>(this IEnumerable<Task<Result<T>>> tasks)
     {
-        var results = await Task.WhenAll(tasks).ConfigureAwait(false);
+        var taskList = tasks.ToList();
+        var results = new Result<T>[taskList.Count];
+
+        for (int i = 0; i < taskList.Count; i++)
+        {
+            var task = await Task.WhenAny(taskList);
+            taskList.Remove(task);
+
+            results[i] = task.IsCompletedSuccessfully
+                ? task.Result
+                : task.Exception!;
+        }
+
         return results.Merge();
     }