Function encode_snapshot 

pub fn encode_snapshot<S: Copy, E: Copy>(
    snapshot: S,
    output: &mut [u8],
    error: E,
    encode: for<'encoder> fn(S, &mut SnapshotEncoder<'encoder, E>) -> Result<(), E>,
) -> Result<usize, E>

Encodes one immutable Copy snapshot after an exact measurement pass.

encode is a function pointer, not a capturing closure. Both passes therefore receive only the same by-value snapshot. An undersized output is unchanged. A final compare-only pass checks every emitted byte exactly. If either later pass violates the measured contract or unwinds, the exact admitted destination is cleared before the error or unwind leaves this function.

Snapshot contract

The snapshot and values it references must remain immutable for the whole call. Do not read clocks, random sources, globals, atomics, cells, or other interior-mutable state from encode. Exact replay detects observable drift, but it is not an authorization mechanism for a deliberately stateful encoder.