Clarify initial frame data detection code

src/protocol.rs

@@ -751,8 +751,8 @@ impl<const N: usize> JulietProtocol<N> {
     ) -> Outcome<CompletedRead, OutgoingMessage> {
         // First, attempt to complete a frame.
         loop {
-            // We do not have enough data to extract a header, indicate and return.
             if buffer.len() < Header::SIZE {
+                // We do not have enough data to extract a header, indicate and return.
                 return Outcome::incomplete(Header::SIZE - buffer.len());
             }
 

src/protocol/multiframe.rs

@@ -212,7 +212,9 @@ impl InitialFrameData {
     /// Returns whether or not the initial frame data describes a complete initial frame.
     #[inline(always)]
     fn is_complete(self) -> bool {
-        self.segment_len >= self.payload_size as usize
+        debug_assert!(self.segment_len <= self.payload_size as usize);
+
+        self.segment_len == self.payload_size as usize
     }
 }