# tracing::field - Rust
API documentation for the Rust `field` mod in crate `tracing`.
Keywords: rust, rustlang, rust-lang, field

# Module tracing::field [−] [src]

Structured data associated with `Span`s and `Event`s.

## Structs

DebugValue | A `Value` which serializes as a string using `fmt::Debug`.
DisplayValue | A `Value` which serializes using `fmt::Display`.
Empty | An empty field.
Field | An opaque key allowing O(1) access to a field in a `Span`'s key-value data.
FieldSet | Describes the fields present on a span.
Iter | An iterator over a set of fields.
ValueSet | A set of fields and values for a span.

## Traits

AsField | Trait implemented to allow a type to be used as a field key.
Value | A field value of an erased type.
Visit | Visits typed values.

## Functions

debug | Wraps a type implementing `fmt::Debug` as a `Value` that can be recorded using its `Debug` implementation.
display | Wraps a type implementing `fmt::Display` as a `Value` that can be recorded using its `Display` implementation.