[Docs] Streaming example diff logic for reasoning_details doesn't match actual API behavior

[wakaka6]

Problem

In the OpenAI-compatible API streaming example, reasoning_details is processed with a diff approach:

reasoning_text = detail["text"]
new_reasoning = reasoning_text[len(reasoning_buffer):]
reasoning_buffer = reasoning_text

This assumes reasoning_details[].text is cumulative (full text so far), requiring a diff against the buffer to extract the new portion.

Actual Behavior

Testing against api.minimaxi.com/v1 with MiniMax-M2.7, reasoning_details[].text returns incremental text, not cumulative:

chunk1: text="The user"
chunk2: text=" is asking how I am, which is a simple greeting."

chunk2 does not contain chunk1's "The user" — it's already just the new part.

Bug

Applying diff logic to incremental text truncates the beginning of each chunk:

chunk1: buf="", text="The user", text[0:] = "The user"       ✅ happens to work
chunk2: buf="The user"(len=8), text=" is asking...", text[8:] = "king..."  ❌ truncated

Reproduction

from openai import OpenAI

client = OpenAI(
    api_key="sk-xxx",
    base_url="https://api.minimaxi.com/v1",
)

stream = client.chat.completions.create(
    model="MiniMax-M2.7",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Hi, how are you?"},
    ],
    extra_body={"reasoning_split": True},
    stream=True,
)

for chunk in stream:
    if (
        hasattr(chunk.choices[0].delta, "reasoning_details")
        and chunk.choices[0].delta.reasoning_details
    ):
        for detail in chunk.choices[0].delta.reasoning_details:
            if "text" in detail:
                text = detail["text"]
                print(f"len={len(text)} text={repr(text)}")

Suggested Fix

If reasoning_details[].text is incremental, the example should simply concatenate:

for detail in chunk.choices[0].delta.reasoning_details:
    if "text" in detail:
        text = detail["text"]
        print(text, end="", flush=True)
        reasoning_buffer += text

Also, if api.minimax.io (international) and api.minimaxi.com (China mainland) behave differently for this field, it would be helpful to note that in the docs.

[wakaka6]

The en version has same problame.