Struct StreamEvent 

pub struct StreamEvent {
    pub event_type: String,
    pub delta: Option<StreamDelta>,
    pub tool_use: Option<StreamToolUse>,
    pub tool_use_start: Option<StreamToolUseStart>,
    pub tool_use_input_delta: Option<StreamToolUseInputDelta>,
    pub tool_use_complete: Option<StreamToolUseComplete>,
    pub usage: Option<ChatUsage>,
    pub error: Option<String>,
    pub done: bool,
}

A single event from an SSE chat stream.

Tool-use streaming uses a triplet of events since v0.7: tool_use_start carries tool_use_start, tool_use_input_delta carries tool_use_input_delta, and tool_use_complete carries tool_use_complete. The legacy atomic tool_use event is still emitted by backends that haven’t shipped the triplet yet — for new code, prefer the triplet fields.

Fields

event_type: String

Event type: “content_delta”, “thinking_delta”, “tool_use_start”, “tool_use_input_delta”, “tool_use_complete”, “tool_use” (legacy), “usage”, “heartbeat”, “error”, “done”.

delta: Option<StreamDelta>

Incremental text for content_delta and thinking_delta events.

tool_use: Option<StreamToolUse>

Populated for legacy atomic tool_use events.

tool_use_start: Option<StreamToolUseStart>

Populated for tool_use_start events.

tool_use_input_delta: Option<StreamToolUseInputDelta>

Populated for tool_use_input_delta events.

tool_use_complete: Option<StreamToolUseComplete>

Populated for tool_use_complete events.

usage: Option<ChatUsage>

Populated for usage events.

error: Option<String>

Populated for error events.

done: bool

True when the stream is complete.

Trait Implementations

impl Clone for StreamEvent

fn clone(&self) -> StreamEvent

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StreamEvent

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

Formats the value using the given formatter.