message: added back tag_byte methods
diff: @@ -185,6 +185,10 @@ impl ExecutionResult {
  &*EXECUTION_RESULT
  }
  + fn tag_byte(&self) -> Option<u8> {
  + self.tag().to_u8()
  + }
  +
  fn tag(&self) -> ExecutionResultTag {
  match self {
  ExecutionResult::Failure {
  @@ -253,7 +257,9 @@ impl Distribution<ExecutionResult> for Standard {
  impl ToBytes for ExecutionResult {
  fn to_bytes(&self) -> Result<Vec<u8>, bytesrepr::Error> {
  let mut buffer = bytesrepr::allocate_buffer(self)?;
  - let tag_byte = self.tag().to_u8().ok_or(bytesrepr::Error::Formatting)?;
  + let tag_byte = self
  + .tag_byte()
  + .ok_or_else(|| bytesrepr::Error::Formatting)?;
  buffer.push(tag_byte);
  match self {
  ExecutionResult::Failure {
  @@ -437,6 +443,9 @@ pub enum OpKind {
  }
  impl OpKind {
  + fn tag_byte(&self) -> Option<u8> {
  + self.tag().to_u8()
  + }
  fn tag(&self) -> OpTag {
  match self {
  OpKind::Read => OpTag::Read,
  @@ -449,7 +458,9 @@ impl OpKind {
  impl ToBytes for OpKind {
  fn to_bytes(&self) -> Result<Vec<u8>, bytesrepr::Error> {
  - let tag_bytes = self.tag().to_u8().ok_or(bytesrepr::Error::Formatting)?;
  + let tag_bytes = self
  + .tag_byte()
  + .ok_or_else(|| bytesrepr::Error::Formatting)?;
  tag_bytes.to_bytes()
  }
  @@ -549,6 +560,9 @@ pub enum Transform {
  }
  impl Transform {
  + fn tag_byte(&self) -> Option<u8> {
  + self.tag().to_u8()
  + }
  fn tag(&self) -> TransformTag {
  match self {
  Transform::Identity => TransformTag::Identity,
  @@ -576,7 +590,9 @@ impl Transform {
  impl ToBytes for Transform {
  fn to_bytes(&self) -> Result<Vec<u8>, bytesrepr::Error> {
  let mut buffer = bytesrepr::allocate_buffer(self)?;
  - let tag_bytes = self.tag().to_u8().ok_or(bytesrepr::Error::Formatting)?;
  + let tag_bytes = self
  + .tag_byte()
  + .ok_or_else(|| bytesrepr::Error::Formatting)?;
  buffer.insert(0, tag_bytes);
  match self {
  Transform::Identity => {}
  