Enum aws_sdk_elasticache::types::AzMode
source · #[non_exhaustive]pub enum AzMode {
CrossAz,
SingleAz,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against AzMode
, 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 azmode = unimplemented!();
match azmode {
AzMode::CrossAz => { /* ... */ },
AzMode::SingleAz => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when azmode
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant AzMode::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
AzMode::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 AzMode::NewFeature
is defined.
Specifically, when azmode
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on AzMode::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
CrossAz
SingleAz
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl Ord for AzMode
impl Ord for AzMode
source§impl PartialEq for AzMode
impl PartialEq for AzMode
source§impl PartialOrd for AzMode
impl PartialOrd for AzMode
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 AzMode
impl StructuralEq for AzMode
impl StructuralPartialEq for AzMode
Auto Trait Implementations§
impl RefUnwindSafe for AzMode
impl Send for AzMode
impl Sync for AzMode
impl Unpin for AzMode
impl UnwindSafe for AzMode
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.