Struct returned by embedding generation calls.
Summary
Types
@type usage() :: map()
Optional provider-reported usage data.
Recognized keys are :input_tokens, :output_tokens,
:cache_creation_input_tokens, :cache_read_input_tokens,
:reasoning_tokens, :input_cost, :output_cost, :cache_read_cost,
:cache_write_cost, :reasoning_cost, :total_cost, and :currency.
All keys are optional; adapters may include additional keys.