返回对聊天补全客户端的引用。
使用此客户端执行聊天补全，包括流式响应、工具调用和推理模式交互。
# 示例
## 基本聊天补全
```rust,no_run
use openai4rs::*;
use dotenvy::dotenv;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
dotenv().ok();
let client = OpenAI::from_env()?;
let messages = vec![user!("Hello, how are you?")];
let response = client
.chat()
.create(ChatParam::new("Qwen/Qwen3-235B-A22B-Instruct-2507", &messages))
.await?;
println!("Response: {:#?}", response);
Ok(())
}
```
## 流式聊天补全
```rust,no_run
use futures::StreamExt;
use openai4rs::*;
use dotenvy::dotenv;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
dotenv().ok();
let client = OpenAI::from_env()?;
let messages = vec![user!("Tell me a story")];
let mut stream = client
.chat()
.create_stream(
ChatParam::new("Qwen/Qwen3-235B-A22B-Instruct-2507", &messages)
.max_completion_tokens(64),
)
.await?;
while let Some(chunk) = stream.next().await {
let chunk = chunk?;
if let Some(choice) = chunk.choices.first() {
if let Some(content) = &choice.delta.content {
print!("{}", content);
}
}
}
Ok(())
}
```