Add Event, KeyedEvent and StringKeyedEvent types (#27)

dev/restate/events.proto

@@ -0,0 +1,52 @@
+// Copyright (c) 2023 - Restate Software, Inc., Restate GmbH
+//
+// This file is part of the Restate service protocol, which is
+// released under the MIT license.
+//
+// You can find a copy of the license in file LICENSE in the root
+// directory of this repository or package, or at
+// https://github.com/restatedev/proto/blob/main/LICENSE
+
+syntax = "proto3";
+
+package dev.restate;
+
+import "dev/restate/ext.proto";
+import "google/protobuf/empty.proto";
+import "google/protobuf/struct.proto";
+
+option java_multiple_files = true;
+option java_package = "dev.restate.generated";
+option go_package = "restate.dev/sdk-go/pb";
+
+message Event {
+  // Payload
+  bytes payload = 2;
+
+  // Metadata
+  string source = 3;
+
+  // This is filled by the source to retain ordering guarantees, depending on the source type
+  bytes ordering_key = 1 [(dev.restate.ext.field) = KEY];
+  map<string, string> attributes = 15;
+}
+
+message KeyedEvent {
+  // Payload
+  bytes key = 1 [(dev.restate.ext.field) = KEY];
+  bytes payload = 2;
+
+  // Metadata
+  string source = 3;
+  map<string, string> attributes = 15;
+}
+
+message StringKeyedEvent {
+  // Payload
+  string key = 1 [(dev.restate.ext.field) = KEY];
+  bytes payload = 2;
+
+  // Metadata
+  string source = 3;
+  map<string, string> attributes = 15;
+}