//! Common types and utilities shared across the `openai4rs` crate.
//!
//! This module contains types and utilities that are used by multiple
//! other modules within the `openai4rs` crate. These types often
//! represent shared data structures or provide common functionality.
//!
//! # Key Components
//!
//! - [`CompletionGeneric`]: A generic struct representing the common fields
//! of a completion response.
//! - [`CompletionUsage`]: Represents token usage statistics for a completion.
//! - [`ServiceTier`]: Represents the service tier of the model.