#[non_exhaustive]pub enum MetricStatistic {
Average,
Maximum,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against MetricStatistic, 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 metricstatistic = unimplemented!();
match metricstatistic {
MetricStatistic::Average => { /* ... */ },
MetricStatistic::Maximum => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when metricstatistic represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant MetricStatistic::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
MetricStatistic::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 MetricStatistic::NewFeature is defined.
Specifically, when metricstatistic represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on MetricStatistic::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis 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
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§
source§impl MetricStatistic
impl MetricStatistic
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for MetricStatistic
impl AsRef<str> for MetricStatistic
source§impl Clone for MetricStatistic
impl Clone for MetricStatistic
source§fn clone(&self) -> MetricStatistic
fn clone(&self) -> MetricStatistic
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for MetricStatistic
impl Debug for MetricStatistic
source§impl Display for MetricStatistic
impl Display for MetricStatistic
source§impl From<&str> for MetricStatistic
impl From<&str> for MetricStatistic
source§impl FromStr for MetricStatistic
impl FromStr for MetricStatistic
source§impl Hash for MetricStatistic
impl Hash for MetricStatistic
source§impl Ord for MetricStatistic
impl Ord for MetricStatistic
source§fn cmp(&self, other: &MetricStatistic) -> Ordering
fn cmp(&self, other: &MetricStatistic) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for MetricStatistic
impl PartialEq for MetricStatistic
source§impl PartialOrd for MetricStatistic
impl PartialOrd for MetricStatistic
impl Eq for MetricStatistic
impl StructuralPartialEq for MetricStatistic
Auto Trait Implementations§
impl Freeze for MetricStatistic
impl RefUnwindSafe for MetricStatistic
impl Send for MetricStatistic
impl Sync for MetricStatistic
impl Unpin for MetricStatistic
impl UnwindSafe for MetricStatistic
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
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit)source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left is true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left(&self) returns true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read more