Ok Garmin, save video

Implement Replayer, a component that replays events in sequence order even when they arrive out of order.

This models a common infrastructure pattern: buffering, reordering, and bounded memory usage.

Each event has:

• seq: a sequence number
• payload: an opaque value you should replay in order

• Initializes the replayer.
• The next expected sequence number is start_seq.
• max_buffer is the maximum number of distinct out-of-order sequence numbers that may be buffered at once.

• Adds an event (seq, payload) to the replayer.
• Returns any payloads that became replayable as a result of this call, in increasing sequence order starting from the current expected sequence.
• If the event’s seq is a duplicate of one already seen (buffered or already replayed), it must be ignored.
• If buffering this event would cause the number of buffered distinct sequence numbers to exceed max_buffer, you must signal failure by printing error.

• Payloads may only be returned when the replayer has a contiguous run beginning at the expected sequence. If it is not possible, print null.
• After replaying sequence s, the next expected sequence becomes s + 1.

• This is an incremental component, not a batch sorting task.
• Correct handling of duplicates, gaps, and bounded buffering is required.