Chatoyant_tokens.CostSourceToken usage and cost data shared by core and provider layers.
type usage = {input_tokens : int;output_tokens : int;reasoning_tokens : int;cached_tokens : int;cache_write_tokens : int;total_tokens : int;actual_cost_usd : float option;}type pricing = {input_per_million : float;output_per_million : float;cached_per_million : float option;cache_write_per_million : float option;cache_write_1h_per_million : float option;per_image : float option;per_second : float option;}type result = {input : float;output : float;cached : float;cache_write : float;actual_usd : float option;total : float;}type cost_per_token = {per_token_input : float;per_token_output : float;per_token_cached : float;per_token_cache_write : float;}