useGetLocks
This Enterprise Edition hook gets all the locks for a given resource. Calls 
dataProvider.getLocks() on mount.
Usage
import { useGetLocks } from '@react-admin/ra-realtime';
const { data } = useGetLocks('posts');
Here is how to use it in a custom <DataTable>, to disable edit and delete buttons for locked records:
const MyPostGrid = () => {
    const resource = useResourceContext();
    const { data: locks } = useGetLocks(resource);
    return (
        <DataTable
            bulkActionButtons={false}
        >
            <DataTable.Col label="Title">
                <MyPostTitle locks={locks} />
            </DataTable.Col>
            <DataTable.Col label="Actions" align="right">
                <MyPostActions locks={locks} />
            </DataTable.Col>
        </DataTable>
    );
};
const MyPostTitle = ({ locks }: { locks: Lock[] }) => {
    const record = useRecordContext();
    const lock = locks.find(l => l.recordId === record.id);
    return (
        <>
            <TextField source="title" />
            {lock && (
                <span style={{ color: 'red' }}>
                    {` (Locked by ${lock.identity})`}
                </span>
            )}
        </>
    );
};
const MyPostActions = ({ locks }: { locks: Lock[] }) => {
    const record = useRecordContext();
    const locked = locks.find(l => l.recordId === record.id);
    return (
        <>
            <DeleteButton disabled={!!locked} />
            <LockableEditButton disabled={!!locked} />
        </>
    );
};
