The variable names in the usage
object returned by the Gemini API using OpenAI compatibility mode are named in camelCase instead of snake_case.
CompletionUsage(
completion_tokens=None,
prompt_tokens=None,
total_tokens=None,
completion_tokens_details=None,
prompt_tokens_details=None,
completionTokens=33,
promptTokens=19,
totalTokens=52,
)