Enum StateValidity 

#[non_exhaustive]
pub enum StateValidity {
    Valid,
    Pending,
    Invalid,
}

What a bind means for state an application derived from an earlier one.

The answer to “may I keep what I computed?” has three values, not two, and a client that offered a boolean would have to guess one of them. See Continuity::state_validity.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Valid

Keep it. The same session came back with everything intact.

Pending

Not known yet. A recovery is in flight, and whether anything was lost is something only the server can say — it does, in the SessionEvent::Recovered that follows immediately. Hold your state and decide when Recovery::is_lossless answers.

Invalid

Discard it. Nothing carries over, and the snapshots that follow are what to rebuild from.

Trait Implementations

impl Clone for StateValidity

fn clone(&self) -> StateValidity

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for StateValidity

impl Debug for StateValidity

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for StateValidity

impl Hash for StateValidity

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for StateValidity

fn cmp(&self, other: &StateValidity) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for StateValidity

fn eq(&self, other: &StateValidity) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for StateValidity

fn partial_cmp(&self, other: &StateValidity) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for StateValidity