#[non_exhaustive]pub enum EbsMetricName {
VolumeReadBytesPerSecond,
VolumeReadOpsPerSecond,
VolumeWriteBytesPerSecond,
VolumeWriteOpsPerSecond,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against EbsMetricName
, 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 ebsmetricname = unimplemented!();
match ebsmetricname {
EbsMetricName::VolumeReadBytesPerSecond => { /* ... */ },
EbsMetricName::VolumeReadOpsPerSecond => { /* ... */ },
EbsMetricName::VolumeWriteBytesPerSecond => { /* ... */ },
EbsMetricName::VolumeWriteOpsPerSecond => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when ebsmetricname
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant EbsMetricName::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
EbsMetricName::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 EbsMetricName::NewFeature
is defined.
Specifically, when ebsmetricname
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on EbsMetricName::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
VolumeReadBytesPerSecond
VolumeReadOpsPerSecond
VolumeWriteBytesPerSecond
VolumeWriteOpsPerSecond
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 EbsMetricName
impl EbsMetricName
source§impl EbsMetricName
impl EbsMetricName
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 EbsMetricName
impl AsRef<str> for EbsMetricName
source§impl Clone for EbsMetricName
impl Clone for EbsMetricName
source§fn clone(&self) -> EbsMetricName
fn clone(&self) -> EbsMetricName
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for EbsMetricName
impl Debug for EbsMetricName
source§impl Display for EbsMetricName
impl Display for EbsMetricName
source§impl From<&str> for EbsMetricName
impl From<&str> for EbsMetricName
source§impl FromStr for EbsMetricName
impl FromStr for EbsMetricName
source§impl Hash for EbsMetricName
impl Hash for EbsMetricName
source§impl Ord for EbsMetricName
impl Ord for EbsMetricName
source§fn cmp(&self, other: &EbsMetricName) -> Ordering
fn cmp(&self, other: &EbsMetricName) -> 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 EbsMetricName
impl PartialEq for EbsMetricName
source§fn eq(&self, other: &EbsMetricName) -> bool
fn eq(&self, other: &EbsMetricName) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for EbsMetricName
impl PartialOrd for EbsMetricName
source§fn partial_cmp(&self, other: &EbsMetricName) -> Option<Ordering>
fn partial_cmp(&self, other: &EbsMetricName) -> 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 EbsMetricName
impl StructuralPartialEq for EbsMetricName
Auto Trait Implementations§
impl Freeze for EbsMetricName
impl RefUnwindSafe for EbsMetricName
impl Send for EbsMetricName
impl Sync for EbsMetricName
impl Unpin for EbsMetricName
impl UnwindSafe for EbsMetricName
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<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