feat(task): add task support (SEP-1686) (#536)

Signed-off-by: jokemanfire <hu.dingyang@zte.com.cn>

crates/rmcp/tests/test_task.rs

@@ -0,0 +1,77 @@
+use std::{any::Any, time::Duration};
+
+use rmcp::task_manager::{
+    OperationDescriptor, OperationMessage, OperationProcessor, OperationResultTransport,
+};
+
+struct DummyTransport {
+    id: String,
+    value: u32,
+}
+
+impl OperationResultTransport for DummyTransport {
+    fn operation_id(&self) -> &String {
+        &self.id
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+}
+
+#[tokio::test]
+async fn executes_enqueued_future() {
+    let mut processor = OperationProcessor::new();
+    let descriptor = OperationDescriptor::new("op1", "dummy");
+    let future = Box::pin(async {
+        tokio::time::sleep(Duration::from_millis(10)).await;
+        Ok(Box::new(DummyTransport {
+            id: "op1".to_string(),
+            value: 42,
+        }) as Box<dyn OperationResultTransport>)
+    });
+
+    processor
+        .submit_operation(OperationMessage::new(descriptor, future))
+        .expect("submit operation");
+
+    tokio::time::sleep(Duration::from_millis(30)).await;
+    let results = processor.collect_completed_results();
+    assert_eq!(results.len(), 1);
+    let payload = results[0]
+        .result
+        .as_ref()
+        .unwrap()
+        .as_any()
+        .downcast_ref::<DummyTransport>()
+        .unwrap();
+    assert_eq!(payload.value, 42);
+}
+
+#[tokio::test]
+async fn rejects_duplicate_operation_ids() {
+    let mut processor = OperationProcessor::new();
+    let descriptor = OperationDescriptor::new("dup", "dummy");
+    let future = Box::pin(async {
+        Ok(Box::new(DummyTransport {
+            id: "dup".to_string(),
+            value: 1,
+        }) as Box<dyn OperationResultTransport>)
+    });
+    processor
+        .submit_operation(OperationMessage::new(descriptor, future))
+        .expect("first submit");
+
+    let descriptor_dup = OperationDescriptor::new("dup", "dummy");
+    let future_dup = Box::pin(async {
+        Ok(Box::new(DummyTransport {
+            id: "dup".to_string(),
+            value: 2,
+        }) as Box<dyn OperationResultTransport>)
+    });
+
+    let err = processor
+        .submit_operation(OperationMessage::new(descriptor_dup, future_dup))
+        .expect_err("duplicate should fail");
+    assert!(format!("{err}").contains("already running"));
+}