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Field | Description |
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Offset | This is the offset used in kafka as the log sequence number. When the producer is sending messages it doesn't actually know the offset and can fill in any value here it likes. |
Crc | The CRC is the CRC32 of the remainder of the message bytes. This is used to check the integrity of the message on the broker and consumer. |
MagicByte | This is a version id used to allow backwards compatible evolution of the message binary format. |
Attributes | This byte holds metadata attributes about the message. The lowest 3 2 bits contain the compression codec used for the message. The other bits should be set to 0. |
Key | The key is an optional message key that was used for partition assignment. The key can be null. |
Value | The value is the actual message contents as an opaque byte array. Kafka supports recursive messages in which case this may itself contain a message set. The message can be null. |
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