What Is Buffered Output?

Buffered output is the practice of accumulating written bytes in an in-memory buffer and sending them to the destination in batches rather than one at a time. Fewer, larger writes are more efficient, but the data is not visible until the buffer is flushed. A crash before a flush can lose the buffered content.

Why it matters

Buffering is why a crashed CI step can show truncated logs that stop short of the actual failure point. Forcing a flush or disabling buffering makes log output appear in real time for debugging.

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