// data that must be copied to the helper threads (the current position and
// search stack, alpha, beta, the search depth, etc.), and we tell our
// helper threads that they have been assigned work. This will cause them
// data that must be copied to the helper threads (the current position and
// search stack, alpha, beta, the search depth, etc.), and we tell our
// helper threads that they have been assigned work. This will cause them