add equals/hashCode to avoid coder warning

[scwhittle]

Example warning

WARNING: Can't verify serialized elements of type OffsetHolder have well defined equals method. This may produce incorrect results on some PipelineRunner implementations
    Feb 20, 2025 11:02:40 AM org.apache.beam.sdk.util.MutationDetectors$CodedValueMutationDetector verifyUnmodifiedThrowingCheckedExceptions
    WARNING: Coder of type class org.apache.beam.sdk.coders.KvCoder has a #structuralValue method which does not return true when the encoding of the elements is equal. Element KV{{topic=any, from=1, to=3, delay=0.2}, org.apache.beam.io.debezium.KafkaSourceConsumerFn$OffsetHolder@58983367}
    Feb 20, 2025 11:02:40 AM org.apache.beam.sdk.util.MutationDetectors$CodedValueMutationDetector verifyUnmodifiedThrowingCheckedExceptions

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[ahmedabu98]

Thanks, left a comment

Also wondering if we could set explicit types for OffsetHolder's history and offset fields (out of scope for this PR but it could be an improvement)

[ahmedabu98]

I see that history is a List<?> but in practice below it is a List<byte[]>. Is this not problematic? As it would compare byte array references instead of the content.

[scwhittle]

Thanks, added logic to do deeper comparison and added a test of equality.

[ahmedabu98]

Thanks! LGTM

just need to add an import and get spotless to run green

[ahmedabu98]

missing an import for StandardCharsets

[scwhittle]

remaining spotless error is unrelated