Function print_stream 

pub async fn print_stream(
    stream: &mut (impl StreamExt<Item = StreamPart> + Unpin),
    print_updates: bool,
) -> String

Stream graph execution and print tokens to stdout in real-time.

Handles the common streaming boilerplate in examples. Tokens from StreamMode::Custom are printed inline (typewriter style). Node completion updates from StreamMode::Updates are printed as [update] lines. Thinking content is printed in dim gray with a [Thinking] prefix.

Returns the collected token text.

Example

use langgraph::prelude::*;
use langgraph_prebuilt::print_stream;

let mut stream = app.astream(&input, &RunnableConfig::new(), vec![StreamMode::Custom, StreamMode::Updates]);
let text = print_stream(&mut stream, true).await;
println!("Final: {}", text);