Constant MAX_PAYLOAD_SIZE_BYTES 

pub const MAX_PAYLOAD_SIZE_BYTES: u64 = _; // 2_097_152u64

Assumed maximum size, in bytes, of a single payload in the retry queue.

The deprecated forwarder_retry_queue_max_size setting bounds the retry queue by payload count, while the queue itself is bounded by bytes. Converting between the two requires assuming a per-payload size, and this value matches the Agent’s own assumption so that the same configuration yields the same byte budget in ADP and the Agent.