Function record_llm_usage 

pub fn record_llm_usage(usage: &LlmUsage)

Available on crate feature telemetry only.

Record LLM token usage on the current span.

Call this after receiving the final LlmResponse to populate the gen_ai.usage.* fields declared by llm_generate_span.

Fields are only recorded when present (non-zero / Some). This is safe to call even if the current span was not created by llm_generate_span — unknown fields are silently ignored by tracing.

Example

use adk_telemetry::{LlmUsage, record_llm_usage};
let usage = LlmUsage {
    input_tokens: 100,
    output_tokens: 50,
    total_tokens: 150,
    cache_read_tokens: Some(80),
    ..Default::default()
};
record_llm_usage(&usage);