Module envelope 

Message envelope for reliable delivery and synchronization.

Every message between client and server is wrapped in an envelope that provides:

• Sequence numbers for ordering and acknowledgment
• Timestamps for clock synchronization
• Piggyback acknowledgments to reduce round trips

Wire Format

The envelope is optional for backward compatibility. Messages can be sent either as raw payloads (legacy) or wrapped in envelopes (new protocol).

// Legacy format (still supported)
{ "type": "heartbeat" }

// Envelope format
{
  "seq": 42,
  "ack": 41,
  "ts": 1701234567890,
  "payload": { "type": "heartbeat" }
}

Structs

Envelope

Message envelope wrapping any payload with delivery metadata.

Enums

MaybeEnveloped

Either an enveloped message or a raw payload (for backward compatibility).