自定义 backend¶

class MyBackend(private val client: MyClient) : ChatBackend {
    override fun stream(history: List<Message>): Flow<ChatEvent> = flow {
        client.run(history.last().text).collect { e ->
            when (e) {
                is MyText -> emit(ChatEvent.TextDelta("answer", e.chunk))
                is MyToolCall -> emit(ChatEvent.ToolInputAvailable(e.id, e.name, e.argsJson, kind = ToolKind.Function))
                is MyToolResult -> emit(ChatEvent.ToolOutput(e.id, e.text))
                is MyHandoff -> emit(ChatEvent.ToolInputAvailable(e.id, "handoff", "{}", kind = ToolKind.Delegation(e.agent, e.task)))
            }
        }
        emit(ChatEvent.Finish)
    }
}