sequenceDiagram
    participant Peer as Peer/Requestor
    participant Gossip as GossipHandler
    participant Pool as BlockPool
    participant Tree as BlockTree
    participant Mempool as Mempool

    Peer->>Gossip: GET_DATA(block_hash)
    Gossip->>Pool: get_cached_block_body(block_hash)
    alt found in recently_processed / pool cache
        Pool-->>Gossip: Arc<BlockBody>
        Gossip-->>Peer: block body
    else not in pool
        Gossip->>Tree: get_sealed_block(block_hash)
        alt found in BlockTree
            Tree-->>Gossip: Arc<SealedBlock> (body)
            Gossip-->>Peer: block body
        else not in BlockTree
            Gossip->>Mempool: reconstruct body from header / mempool DB
            alt reconstruction success
                Mempool-->>Gossip: Arc<BlockBody>
                Gossip-->>Peer: block body
            else failure
                Mempool-->>Gossip: None / error
                Gossip-->>Peer: None / error
            end
        end
    end