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