#[non_exhaustive]
pub enum MessageSystemAttributeNameForSends {
AwsTraceHeader,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against MessageSystemAttributeNameForSends
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let messagesystemattributenameforsends = unimplemented!();
match messagesystemattributenameforsends {
MessageSystemAttributeNameForSends::AwsTraceHeader => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when messagesystemattributenameforsends
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant MessageSystemAttributeNameForSends::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
MessageSystemAttributeNameForSends::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant MessageSystemAttributeNameForSends::NewFeature
is defined.
Specifically, when messagesystemattributenameforsends
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on MessageSystemAttributeNameForSends::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
AwsTraceHeader
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl Clone for MessageSystemAttributeNameForSends
impl Clone for MessageSystemAttributeNameForSends
source§fn clone(&self) -> MessageSystemAttributeNameForSends
fn clone(&self) -> MessageSystemAttributeNameForSends
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl From<&str> for MessageSystemAttributeNameForSends
impl From<&str> for MessageSystemAttributeNameForSends
source§impl Ord for MessageSystemAttributeNameForSends
impl Ord for MessageSystemAttributeNameForSends
source§fn cmp(&self, other: &MessageSystemAttributeNameForSends) -> Ordering
fn cmp(&self, other: &MessageSystemAttributeNameForSends) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<MessageSystemAttributeNameForSends> for MessageSystemAttributeNameForSends
impl PartialEq<MessageSystemAttributeNameForSends> for MessageSystemAttributeNameForSends
source§fn eq(&self, other: &MessageSystemAttributeNameForSends) -> bool
fn eq(&self, other: &MessageSystemAttributeNameForSends) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<MessageSystemAttributeNameForSends> for MessageSystemAttributeNameForSends
impl PartialOrd<MessageSystemAttributeNameForSends> for MessageSystemAttributeNameForSends
source§fn partial_cmp(
&self,
other: &MessageSystemAttributeNameForSends
) -> Option<Ordering>
fn partial_cmp(
&self,
other: &MessageSystemAttributeNameForSends
) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for MessageSystemAttributeNameForSends
impl StructuralEq for MessageSystemAttributeNameForSends
impl StructuralPartialEq for MessageSystemAttributeNameForSends
Auto Trait Implementations§
impl RefUnwindSafe for MessageSystemAttributeNameForSends
impl Send for MessageSystemAttributeNameForSends
impl Sync for MessageSystemAttributeNameForSends
impl Unpin for MessageSystemAttributeNameForSends
impl UnwindSafe for MessageSystemAttributeNameForSends
Blanket Implementations§
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.