GroqUsage constructor
      
      GroqUsage({})
     
    
The usage of the groq resources 
It contains the number of tokens used in the prompt and completion 
It also contains the time taken in the prompt and completion 
It is used for chats and audio responses 
Audio responses just have a completion time, prompt tokens and completion tokens
Implementation
GroqUsage({
  required this.promptTokens,
  required this.completionTokens,
  required this.promptTime,
  required this.completionTime,
});