What is streaming in the OpenAI API and how do you implement it?

from openai import OpenAI

client = OpenAI()

# Chat Completions streaming
with client.chat.completions.stream(
    model="gpt-5.5",
    messages=[{"role": "user", "content": "Write a Python web scraper."}],
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)
    # Access final complete response:
    final = stream.get_final_completion()

# Responses API streaming
with client.responses.stream(
    model="gpt-5.5",
    input="Explain async/await in Python with examples.",
) as stream:
    for event in stream:
        # Events: response.created, response.in_progress,
        # response.output_item.added, response.content_part.delta,
        # response.completed, etc.
        if event.type == "response.output_text.delta":
            print(event.delta, end="", flush=True)
    final_response = stream.get_final_response()

# Async streaming for FastAPI/async applications:
async def stream_response():
    async with client.responses.stream(
        model="gpt-5.5",
        input="Review this code: ...",
    ) as stream:
        async for text in stream.text_stream:
            yield text  # SSE to browser