Refactors in response to review comments

A few minor refactors, and a more major one that renames
RecordingStore's update_entry_qmdl_size to
update_current_entry_qmdl_size, since the only time we're ever updating
an entry's QMDL size is when it's the current one.

lib/src/diag.rs

@@ -1,6 +1,5 @@
 //! Diag protocol serialization/deserialization
 
-use bytes::Bytes;
 use chrono::{DateTime, FixedOffset};
 use crc::{Algorithm, Crc};
 use deku::prelude::*;
@@ -97,12 +96,6 @@ impl MessagesContainer {
     }
 }
 
-impl From<MessagesContainer> for Bytes {
-    fn from(value: MessagesContainer) -> Self {
-        value.to_bytes().unwrap().into()
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, DekuRead, DekuWrite)]
 pub struct HdlcEncapsulatedMessage {
     pub len: u32,

lib/src/qmdl.rs

@@ -45,14 +45,14 @@ where
     pub async fn write_container(&mut self, container: &MessagesContainer) -> std::io::Result<()> {
         for msg in &container.messages {
             self.writer.write_all(&msg.data).await?;
-            self.writer.flush().await?;
         }
+        self.writer.flush().await?;
         Ok(())
     }
 
-    pub async fn close(mut self) -> std::io::Result<()> {
+    pub async fn close(mut self) -> std::io::Result<usize> {
         self.writer.shutdown().await?;
-        Ok(())
+        self.size().await
     }
 }
 
@@ -298,7 +298,7 @@ mod test {
                 hdlcs.iter().map(|hdlc| hdlc.data.len()).collect(),
             )
         };
-        for truncated_hdlc_i in 1..hdlcs.len() - 1 {
+        for truncated_hdlc_i in 1..hdlcs.len() {
             let whole_bytes: usize = message_lengths.iter().take(truncated_hdlc_i).sum();
             for truncated_byte in 1..message_lengths[truncated_hdlc_i] {
                 let mut truncated_bytes = Cursor::new(&bytes[0..whole_bytes + truncated_byte]);
@@ -360,15 +360,18 @@ mod test {
     async fn run_compressed_reading_and_writing_tests(do_close: bool) {
         let containers = get_test_containers();
         let mut buf = Cursor::new(Vec::new());
-        {
+        let writer_size = {
             let mut writer = QmdlWriter::new(&mut buf);
             for container in &containers {
                 writer.write_container(&container).await.unwrap();
             }
             if do_close {
-                writer.close().await.unwrap();
+                writer.close().await.unwrap()
+            } else {
+                writer.size().await.unwrap()
             }
-        }
+        };
+        assert_eq!(buf.position() as usize, writer_size);
         buf.set_position(0);
         let mut reader = QmdlMessageReader::new(buf).await.unwrap();
         assert!(reader.is_compressed());