Add a processor API to the coordinator

coordinator/src/processor.rs

@@ -0,0 +1,41 @@
+use std::{
+  sync::{Arc, RwLock},
+  collections::VecDeque,
+};
+
+use processor_messages::{ProcessorMessage, CoordinatorMessage};
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct Message {
+  pub id: u64,
+  pub msg: ProcessorMessage,
+}
+
+#[async_trait::async_trait]
+pub trait Processor: 'static + Send + Sync {
+  async fn send(&mut self, msg: CoordinatorMessage);
+  async fn recv(&mut self) -> Message;
+  async fn ack(&mut self, msg: Message);
+}
+
+// TODO: Move this to tests
+pub struct MemProcessor(Arc<RwLock<VecDeque<Message>>>);
+impl MemProcessor {
+  #[allow(clippy::new_without_default)]
+  pub fn new() -> MemProcessor {
+    MemProcessor(Arc::new(RwLock::new(VecDeque::new())))
+  }
+}
+
+#[async_trait::async_trait]
+impl Processor for MemProcessor {
+  async fn send(&mut self, _: CoordinatorMessage) {
+    todo!()
+  }
+  async fn recv(&mut self) -> Message {
+    todo!()
+  }
+  async fn ack(&mut self, _: Message) {
+    todo!()
+  }
+}