Function compute_entry_hash 

pub fn compute_entry_hash(
    seq: u64,
    ts_init: UnixNanos,
    ts_publish: UnixNanos,
    topic: &str,
    payload_type: &str,
    payload: &Bytes,
    headers: &Headers,
) -> EntryHash

Computes the canonical hash of an event store entry.

The hash is domain-separated by a fixed crate-internal prefix and uses big-endian fixed-width framing for every variable-length field so the output depends only on the logical content of the entry, not on the host endianness or the runtime serialization format.