TLV and TV abstractions complete

src/cfdp/pdu/metadata.rs

@@ -1,15 +1,17 @@
+use crate::cfdp::lv::Lv;
 use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
 use crate::cfdp::ChecksumType;
 
-pub struct MetadataParams {
+pub struct MetadataGenericParams {
     closure_requested: bool,
     checksum_type: ChecksumType,
     file_size: u64,
-    //src_file_name:
 }
 
-pub struct MetadataPdu {
+pub struct MetadataPdu<'src_name, 'dest_name> {
     pdu_header: PduHeader,
     file_directive: FileDirectiveType,
-    metadata_params: MetadataParams,
+    metadata_params: MetadataGenericParams,
+    src_file_name: Option<Lv<'src_name>>,
+    dest_file_name: Option<Lv<'dest_name>>,
 }

src/cfdp/pdu/mod.rs

@@ -63,14 +63,21 @@ impl Display for PduError {
                 )
             }
             PduError::ByteConversionError(e) => {
-                write!(f, "low level byte conversion error: {e}")
+                write!(f, "{}", e)
             }
         }
     }
 }
 
 #[cfg(feature = "std")]
-impl Error for PduError {}
+impl Error for PduError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            PduError::ByteConversionError(e) => Some(e),
+            _ => None,
+        }
+    }
+}
 
 impl From<ByteConversionError> for PduError {
     fn from(value: ByteConversionError) -> Self {