Function encode_parallel 

pub fn encode_parallel(
    shared_secret: &[u8],
    plaintext: &[u8],
    aad: &[u8],
    chunk_size: usize,
    pool: Option<&EntropyPool>,
) -> Result<KkParallelPacket>

Encode a large payload in parallel by splitting it into chunks.

Each chunk is encrypted independently via encode_aead (or the pooled variant when a pool is provided). All chunks are processed in parallel using Rayon. A Merkle root over the chunk commitments binds the entire payload together.

Arguments

• shared_secret - the pre-shared key
• plaintext - the full payload to encrypt
• aad - associated data, authenticated on every chunk
• chunk_size - bytes per chunk (use PARALLEL_CHUNK_SIZE for default 1 MiB)
• pool - optional EntropyPool for high-throughput paths