Struct ChatCompletionAccumulator 

pub struct ChatCompletionAccumulator { /* private fields */ }

Assembles streamed ChatCompletionChunks into complete messages.

All choices are accumulated, keyed by their chunk index; the accessors and ChatCompletionAccumulator::into_message default to choice 0 (the only choice unless the request set n > 1).

Fragment semantics follow the official SDKs: content / refusal / tool call arguments concatenate; role, tool call id / type / name and function_call.name are overwritten whenever a fragment carries them; finish_reason and usage are kept from the last chunk that provided them.

Implementations

impl ChatCompletionAccumulator

pub fn new() -> Self

Creates an empty accumulator.

pub fn push(&mut self, chunk: &ChatCompletionChunk)

Merges one chunk into the accumulated state.

pub fn content(&self) -> &str

The accumulated text content of choice 0, empty before any content chunk arrives.

pub fn reasoning_content(&self) -> &str

The accumulated reasoning_content of choice 0 (thinking models).

pub fn reasoning(&self) -> &str

The accumulated reasoning of choice 0.

vLLM streams the chain of thought under reasoning instead of reasoning_content, so against a vLLM backend Self::reasoning_content stays empty and this accessor carries the accumulated thought.

pub fn finish_reason(&self) -> Option<&FinishReason>

The finish_reason of choice 0, once a chunk carries it.

pub fn usage(&self) -> Option<&CompletionUsage>

The token usage, once a chunk carries it (the final chunk when the request set stream_options: {"include_usage": true}).

pub fn function_call(&self) -> Option<&AccumulatedFunctionCall>

The deprecated function_call of choice 0, assembled from its fragments, if the model used the legacy path.

pub fn into_message(self) -> ChatCompletionMessage

Consumes the accumulator, producing the assembled message of choice 0. An accumulator that never saw a choice-0 chunk yields an empty assistant message.

pub fn into_messages(self) -> BTreeMap<u32, ChatCompletionMessage>

Consumes the accumulator, producing every assembled message keyed by its choice index.

Trait Implementations

impl Clone for ChatCompletionAccumulator

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChatCompletionAccumulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ChatCompletionAccumulator

fn default() -> Self

Returns the “default value” for a type.