fix: added API specification documentation for blockstream.proto

Signed-off-by: Matt Peterson <[email protected]>

protos/src/main/protobuf/blockstream.proto

@@ -1,5 +1,21 @@
 syntax = "proto3";
 
+/*-
+ * Copyright (C) 2024 Hedera Hashgraph, LLC
+ *
+ * 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.
+ */
+
 option java_package = "com.hedera.block.protos";
 option java_outer_classname = "BlockStreamServiceGrpcProto";
 
@@ -8,11 +24,34 @@ service BlockStreamGrpc {
     rpc StreamSource(stream BlockResponse) returns (stream Block) {}
 }
 
+/**
+ * A block is a simple message that contains an id and a value.
+ * This specification is a simple example meant to expedite development.
+ * It will be replaced with a PBJ implementation in the future.
+ */
 message Block {
+    /**
+     * The id of the block.  Each block id should be unique.
+     */
     int64 id = 1;
+
+    /**
+     * The value of the block.  The value can be any string.
+     */
     string value = 2;
 }
 
+/**
+ * A block response is a simple message that contains an id.
+ * The block response message is simply meant to disambiguate it
+ * from the original request. This specification is a simple
+ * example meant to expedite development. It will be replaced with
+ * a PBJ implementation in the future.
+ */
 message BlockResponse {
+    /**
+     * The id of the block which was received.  Each block id should
+     * correlate with the id of a Block message id.
+     */
     int64 id = 1;
 }