feat(acp): add observable lifecycle state

Author: loong10k

src/main/java/io/github/easy4j/kimi/acp/KimiAcpState.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018-present, easy-4-java (https://github.com/easy-4-java).
+ *
+ * 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.
+ */
+package io.github.easy4j.kimi.acp;
+
+/**
+ * Observable lifecycle states of a {@link KimiAcpClient}.
+ *
+ * @since 1.0.0
+ */
+public enum KimiAcpState {
+
+    /** Client exists but does not own an ACP transport yet. */
+    NEW,
+
+    /** The child process is being created. */
+    CONNECTING,
+
+    /** The child process exists and the ACP initialize handshake is pending. */
+    INITIALIZING,
+
+    /** ACP initialize completed successfully and requests may be submitted. */
+    READY,
+
+    /** A terminal transport/protocol failure made the connection unusable. */
+    FAILED,
+
+    /** Close has started and new work is rejected. */
+    CLOSING,
+
+    /** All owned resources have been released. */
+    CLOSED
+}