Enum Presence 

pub enum Presence {
    Implicit,
    Explicit,
}

Field presence discipline

Variants

Implicit

Implicit presence. Fields don’t have flag to track presence, and default values are treated as not present.

Used for Proto3 fields.

Explicit

Explicit presence. Fields have flags to track presense.

Use for optional fields.

Trait Implementations

impl Clone for Presence

fn clone(&self) -> Presence

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Presence

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

Formats the value using the given formatter.

impl PartialEq for Presence

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Presence

impl Eq for Presence

impl StructuralPartialEq for Presence