Function cosmwasm_vm::call_migrate_raw

pub fn call_migrate_raw<S: Storage + 'static, A: Api + 'static, Q: Querier + 'static>(
    instance: &mut Instance<S, A, Q>, 
    env: &[u8], 
    msg: &[u8]
) -> VmResult<Vec<u8>>

Calls Wasm export "migrate" and returns raw data from the contract. The result is length limited to prevent abuse but otherwise unchecked.