feat(proto): add frontend message writer

proto/src/writer/frontend.rs

@@ -0,0 +1,40 @@
+use crate::message::frontend::FrontendMessage;
+use crate::writer::oneway::OneWayProtoWriter;
+use async_trait::async_trait;
+
+#[async_trait]
+pub trait FrontendProtoWriter: OneWayProtoWriter<FrontendMessage> {}
+
+#[async_trait]
+impl<W> FrontendProtoWriter for W where W: OneWayProtoWriter<FrontendMessage> {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::message::frontend::QueryData;
+    use crate::writer::protowriter::ProtoWriter;
+    use tokio::io::BufWriter;
+
+    #[tokio::test]
+    async fn test_message_sequence() {
+        let writer = BufWriter::new(Vec::new());
+        let mut writer = ProtoWriter::new(writer);
+
+        writer
+            .write_proto(FrontendMessage::Query(QueryData {
+                query: "SLIME".into(),
+            }))
+            .await
+            .unwrap();
+
+        writer
+            .write_proto(FrontendMessage::Terminate)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            writer.inner.buffer(),
+            vec![b'Q', 0, 0, 0, 10, b'S', b'L', b'I', b'M', b'E', 0, b'X', 0, 0, 0, 4]
+        );
+    }
+}

proto/src/writer/mod.rs

@@ -1,4 +1,4 @@
-
 pub mod backend;
+pub mod frontend;
 pub mod oneway;
 pub mod protowriter;