Struct Usage 

pub struct Usage {
    pub input_tokens: u64,
    pub output_tokens: u64,
    pub cached_input_tokens: u64,
}

Three-field token usage as returned by Gemini’s usageMetadata.

Gemini reports promptTokenCount as including cached content tokens, so the Usage::from_gemini constructor subtracts cachedContentTokenCount from promptTokenCount to get the fresh input count this struct expects.

Fields

input_tokens: u64

Fresh input/prompt tokens (not served from the context cache).

output_tokens: u64

Output / candidate tokens.

cached_input_tokens: u64

Input tokens that were served from a context cache (cache hit).

Implementations

impl Usage

pub fn cache_hit(&self) -> bool

True when the request hit the context cache.

pub fn total_tokens(&self) -> u64

Total tokens billed (input + output + cached_input).

pub fn from_gemini( prompt_token_count: u64, candidates_token_count: u64, cached_content_token_count: u64, ) -> Self

Build a Usage from a Gemini usageMetadata payload.

prompt_token_count includes cached tokens on the wire; this constructor subtracts them so the struct’s fields are disjoint.

Trait Implementations

impl Clone for Usage

fn clone(&self) -> Usage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Usage

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

Formats the value using the given formatter.

impl Default for Usage

fn default() -> Usage

Returns the “default value” for a type.

impl PartialEq for Usage

fn eq(&self, other: &Usage) -> 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 Usage

impl Eq for Usage

impl StructuralPartialEq for Usage