Function handleStreamEvent

packages/ai-claude-code/src/stream/translate.ts:359–434

(
    message: SdkPartialAssistantMessage,
  )

  }

  function* handleStreamEvent(
    message: SdkPartialAssistantMessage,
  ): Generator<StreamChunk> {
    const event = message.event
    if (event.type === 'message_start') {
      partialMessageId = event.message.id ?? genId()
      streamedMessageIds.add(partialMessageId)
    } else if (event.type === 'content_block_start') {
      partialBlockType = event.content_block.type
      if (partialBlockType === 'text') {
        partialTextMessageId = partialMessageId ?? genId()
        partialTextContent = ''
        if (!partialTextStarted) {
          partialTextStarted = true
          yield {
            type: EventType.TEXT_MESSAGE_START,
            messageId: partialTextMessageId,
            model,
            timestamp: now(),
            role: 'assistant',
          }
        }
      } else if (partialBlockType === 'thinking') {
        partialReasoningId = genId()
        yield {
          type: EventType.REASONING_START,
          messageId: partialReasoningId,
          model,
          timestamp: now(),
        }
        yield {
          type: EventType.REASONING_MESSAGE_START,
          messageId: partialReasoningId,
          role: 'reasoning' as const,
          model,
          timestamp: now(),
        }
      }
    } else if (event.type === 'content_block_delta') {
      if (
        event.delta.type === 'text_delta' &&
        partialTextStarted &&
        partialTextMessageId &&
        typeof event.delta.text === 'string'
      ) {
        partialTextContent += event.delta.text
        yield {
          type: EventType.TEXT_MESSAGE_CONTENT,
          messageId: partialTextMessageId,
          model,
          timestamp: now(),
          delta: event.delta.text,
          content: partialTextContent,
        }
      } else if (
        event.delta.type === 'thinking_delta' &&
        partialReasoningId &&
        typeof event.delta.thinking === 'string'