Function encode_outbox_proof 

pub fn encode_outbox_proof(send: B256, root: B256, proof: &[B256]) -> Bytes

ABI-encode the outbox proof return value.

Solidity signature: constructOutboxProof(uint64 size, uint64 leaf) returns (bytes32 send, bytes32 root, bytes32[] proof)

Layout (bytes): [00..32] send [32..64] root [64..96] offset to proof array = 0x60 (96) [96..128] proof.length (uint256) [128..] proof elements