chore: import upstream snapshot with attribution

Sources/DNSServer/Records/DNSBindError.swift

@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2026 Apple Inc. and the container project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+/// Errors that can occur during DNS message serialization/deserialization.
+public enum DNSBindError: Error, CustomStringConvertible {
+    case marshalFailure(type: String, field: String)
+    case unmarshalFailure(type: String, field: String)
+    case unsupportedValue(type: String, field: String)
+    case invalidName(String)
+    case unexpectedOffset(type: String, expected: Int, actual: Int)
+
+    public var description: String {
+        switch self {
+        case .marshalFailure(let type, let field):
+            return "failed to marshal \(type).\(field)"
+        case .unmarshalFailure(let type, let field):
+            return "failed to unmarshal \(type).\(field)"
+        case .unsupportedValue(let type, let field):
+            return "unsupported value for \(type).\(field)"
+        case .invalidName(let reason):
+            return "invalid DNS name: \(reason)"
+        case .unexpectedOffset(let type, let expected, let actual):
+            return "unexpected offset serializing \(type): expected \(expected), got \(actual)"
+        }
+    }
+}