Struct Field

pub struct Field { /* private fields */ }

An opaque key allowing O(1) access to a field in a Span’s key-value data.

As keys are defined by the metadata of a span, rather than by an individual instance of a span, a key may be used to access the same field across all instances of a given span with the same metadata. Thus, when a subscriber observes a new span, it need only access a field by name once, and use the key for that name for all other accesses.

Implementations

impl Field

pub fn callsite(&self) -> Identifier

Available on crate feature cpu_os_threads only.

Returns an Identifier that uniquely identifies the Callsite which defines this field.

pub fn name(&self) -> &'static str

Available on crate feature cpu_os_threads only.

Returns a string representing the name of the field.

pub fn index(&self) -> usize

Available on crate feature cpu_os_threads only.

Returns the index of this field in its FieldSet.

Trait Implementations

impl<'a> AsField for &'a Field

fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field>

Attempts to convert &self into a Field with the specified metadata.

impl AsField for Field

fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field>

Attempts to convert &self into a Field with the specified metadata.

impl AsRef<str> for Field

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Field

fn clone(&self) -> Field

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Field

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

Formats the value using the given formatter.

impl Display for Field

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

Formats the value using the given formatter.

impl Hash for Field

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

where H: Hasher,

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 PartialEq for Field

fn eq(&self, other: &Field) -> 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 Eq for Field