Update NOTICE.txt and add gRPC license headers.

Author: aryan-25

NOTICE.txt

@@ -59,3 +59,12 @@ This product contains a fuzz testing harness derived from Swift Protobuf.
     * https://github.com/apple/swift-protobuf/blob/main/LICENSE.txt
   * HOMEPAGE:
     * https://github.com/apple/swift-protobuf
+
+---
+
+This product contains a graceful shutdown connection manager derived from gRPC Swift NIO Transport.
+
+  * LICENSE (Apache License 2.0):
+    * https://github.com/grpc/grpc-swift-nio-transport/blob/main/LICENSE
+  * HOMEPAGE:
+    * https://github.com/gRPC/gRPC-swift-nio-transport

Sources/NIOHTTP2/NIOHTTP2ServerConnectionManagementHandler+StateMachine.swift

@@ -12,6 +12,22 @@
 //
 //===----------------------------------------------------------------------===//
 
+/*
+ * Copyright 2024, gRPC Authors All rights reserved.
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
 import NIOCore
 
 extension NIOHTTP2ServerConnectionManagementHandler {

Sources/NIOHTTP2/NIOHTTP2ServerConnectionManagementHandler.swift

@@ -12,6 +12,22 @@
 //
 //===----------------------------------------------------------------------===//
 
+/*
+ * Copyright 2024, gRPC Authors All rights reserved.
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
 import NIOCore
 import NIOTLS
 

Tests/NIOHTTP2Tests/NIOHTTP2ServerConnectionManagementHandler+StateMachineTests.swift

@@ -12,6 +12,22 @@
 //
 //===----------------------------------------------------------------------===//
 
+/*
+ * Copyright 2024, gRPC Authors All rights reserved.
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
 import NIOCore
 import Testing
 

Tests/NIOHTTP2Tests/NIOHTTP2ServerConnectionManagementHandlerTests.swift

@@ -12,6 +12,22 @@
 //
 //===----------------------------------------------------------------------===//
 
+/*
+ * Copyright 2024, gRPC Authors All rights reserved.
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
 import NIOCore
 import NIOEmbedded
 import NIOHPACK