Remove the cursor overhead, write is implemented on vec these days

src/blockdata/transaction.rs

@@ -378,10 +378,9 @@ impl Transaction {
             _ => unreachable!()
         };
         // hash the result
-        // TODO: Sanity assert that consensus_encode returned length matches the hashed length in the hasher.
-        let sighash_arr = endian::u32_to_array_le(sighash_u32);
         let mut engine = SigHash::engine();
         tx.consensus_encode(&mut engine).unwrap();
+        let sighash_arr = endian::u32_to_array_le(sighash_u32);
         sighash_arr.consensus_encode(&mut engine).unwrap();
         SigHash::from_engine(engine)
     }

src/consensus/encode.rs

@@ -149,10 +149,10 @@ impl From<psbt::Error> for Error {
 
 /// Encode an object into a vector
 pub fn serialize<T: Encodable + ?Sized>(data: &T) -> Vec<u8> {
-    let mut encoder = Cursor::new(vec![]);
+    let mut encoder = Vec::new();
     let len = data.consensus_encode(&mut encoder).unwrap();
-    assert_eq!(len, encoder.get_ref().len());
-    encoder.into_inner()
+    assert_eq!(len, encoder.len());
+    encoder
 }
 
 /// Encode an object into a hex-encoded string

src/util/misc.rs

@@ -59,11 +59,10 @@ pub fn script_find_and_remove(haystack: &mut Vec<u8>, needle: &[u8]) -> usize {
 
 /// Hash message for signature using Bitcoin's message signing format
 pub fn signed_msg_hash(msg: &str) -> sha256d::Hash {
-    let msg_len = encode::VarInt(msg.len() as u64);
 
-    // TODO: Sanity assert that consensus_encode returned length matches the hashed length in the hasher.
     let mut engine = sha256d::Hash::engine();
     engine.input(MSG_SIGN_PREFIX);
+    let msg_len = encode::VarInt(msg.len() as u64);
     msg_len.consensus_encode(&mut engine).unwrap();
     engine.input(msg.as_bytes());