candidate_pending_availability: RuntimeDescriptor<
    [para_id: number],

        | {
            commitments: {
                head_data: Binary;
                horizontal_messages: { data: Binary; recipient: number }[];
                hrmp_watermark: number;
                new_validation_code?: Binary;
                processed_downward_messages: number;
                upward_messages: Binary[];
            };
            descriptor: {
                core_index: number;
                erasure_root: FixedSizeBinary<32>;
                para_head: FixedSizeBinary<32>;
                para_id: number;
                persisted_validation_data_hash: FixedSizeBinary<32>;
                pov_hash: FixedSizeBinary<32>;
                relay_parent: FixedSizeBinary<32>;
                reserved1: FixedSizeBinary<25>;
                reserved2: FixedSizeBinary<64>;
                session_index: number;
                validation_code_hash: FixedSizeBinary<32>;
                version: number;
            };
        }
        | undefined,
>

Get the receipt of a candidate pending availability. This returns Some for any paras assigned to occupied cores in availability_cores and None otherwise.