Function indy_sys::cache::indy_get_cred_def

#[no_mangle]pub unsafe extern "C" fn indy_get_cred_def(
    command_handle: CommandHandle, 
    pool_handle: PoolHandle, 
    wallet_handle: WalletHandle, 
    submitter_did: CString, 
    id: CString, 
    options_json: CString, 
    cb: Option<ResponseStringCB>
) -> Error