Correct transaction size

The transaction size currently returns the size of the overall block
instead of the individual transaction.  To address this effectively,
the `ExplorerTransaction` `trait` has been updated to require the
ability to specify the payload size of the individual transaction.

src/explorer/query_data.rs

@@ -380,6 +380,7 @@ where
     BlockQueryData<Types>: HeightIndexed,
     Payload<Types>: QueryablePayload<Types>,
     Header<Types>: QueryableHeader<Types> + ExplorerHeader<Types>,
+    <Types as NodeType>::Transaction: ExplorerTransaction,
 {
     type Error = TimestampConversionError;
 
@@ -399,7 +400,7 @@ where
                 block_confirmed: true,
                 offset: offset as u64,
                 num_transactions: block.num_transactions,
-                size: block.size,
+                size: transaction.payload_size(),
                 time: Timestamp(time::OffsetDateTime::from_unix_timestamp(seconds)?),
                 sequencing_fees: vec![],
                 fee_details: vec![],

src/explorer/traits.rs

@@ -66,5 +66,9 @@ pub trait ExplorerTransaction {
     /// a representation of it that adheres to the trait restrictions specified.
     type NamespaceId: Clone + Debug + Serialize + DeserializeOwned + Send + Sync + PartialEq + Eq;
 
+    /// namespace_id returns the namespace id of the individual transaction.
     fn namespace_id(&self) -> Self::NamespaceId;
+
+    /// payload_size returns the size of the payload of the transaction.
+    fn payload_size(&self) -> u64;
 }

src/testing/mocks.rs

@@ -89,6 +89,10 @@ impl ExplorerTransaction for MockTransaction {
     fn namespace_id(&self) -> Self::NamespaceId {
         0
     }
+
+    fn payload_size(&self) -> u64 {
+        self.bytes().len() as u64
+    }
 }
 
 impl HeightIndexed for MockHeader {