#[non_exhaustive]
pub enum CloudWatchMetricsStat {
Average,
Maximum,
Minimum,
SampleCount,
Sum,
P50,
P90,
P99,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against CloudWatchMetricsStat
, 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 cloudwatchmetricsstat = unimplemented!();
match cloudwatchmetricsstat {
CloudWatchMetricsStat::Average => { /* ... */ },
CloudWatchMetricsStat::Maximum => { /* ... */ },
CloudWatchMetricsStat::Minimum => { /* ... */ },
CloudWatchMetricsStat::SampleCount => { /* ... */ },
CloudWatchMetricsStat::Sum => { /* ... */ },
CloudWatchMetricsStat::P50 => { /* ... */ },
CloudWatchMetricsStat::P90 => { /* ... */ },
CloudWatchMetricsStat::P99 => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when cloudwatchmetricsstat
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant CloudWatchMetricsStat::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
CloudWatchMetricsStat::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 CloudWatchMetricsStat::NewFeature
is defined.
Specifically, when cloudwatchmetricsstat
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on CloudWatchMetricsStat::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
Average
Maximum
Minimum
SampleCount
Sum
P50
P90
P99
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for CloudWatchMetricsStat
impl AsRef<str> for CloudWatchMetricsStat
source§impl Clone for CloudWatchMetricsStat
impl Clone for CloudWatchMetricsStat
source§fn clone(&self) -> CloudWatchMetricsStat
fn clone(&self) -> CloudWatchMetricsStat
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for CloudWatchMetricsStat
impl Debug for CloudWatchMetricsStat
source§impl From<&str> for CloudWatchMetricsStat
impl From<&str> for CloudWatchMetricsStat
source§impl FromStr for CloudWatchMetricsStat
impl FromStr for CloudWatchMetricsStat
source§impl Hash for CloudWatchMetricsStat
impl Hash for CloudWatchMetricsStat
source§impl Ord for CloudWatchMetricsStat
impl Ord for CloudWatchMetricsStat
source§fn cmp(&self, other: &CloudWatchMetricsStat) -> Ordering
fn cmp(&self, other: &CloudWatchMetricsStat) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<CloudWatchMetricsStat> for CloudWatchMetricsStat
impl PartialEq<CloudWatchMetricsStat> for CloudWatchMetricsStat
source§fn eq(&self, other: &CloudWatchMetricsStat) -> bool
fn eq(&self, other: &CloudWatchMetricsStat) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<CloudWatchMetricsStat> for CloudWatchMetricsStat
impl PartialOrd<CloudWatchMetricsStat> for CloudWatchMetricsStat
source§fn partial_cmp(&self, other: &CloudWatchMetricsStat) -> Option<Ordering>
fn partial_cmp(&self, other: &CloudWatchMetricsStat) -> 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 CloudWatchMetricsStat
impl StructuralEq for CloudWatchMetricsStat
impl StructuralPartialEq for CloudWatchMetricsStat
Auto Trait Implementations§
impl RefUnwindSafe for CloudWatchMetricsStat
impl Send for CloudWatchMetricsStat
impl Sync for CloudWatchMetricsStat
impl Unpin for CloudWatchMetricsStat
impl UnwindSafe for CloudWatchMetricsStat
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.