Obtain an executor with the blocking.always property.

inline_or_executor< Executor, execution::blocking_t::always_t, InlineExceptionHandling > require(
    const execution::blocking_t::always_t & ) const;

Do not call this function directly. It is intended for use with the require customisation point.

For example:

boost::asio::inline_or_executor<my_executor_type> ex = ...;
auto ex2 = boost::asio::require(ex1,
    boost::asio::execution::blocking.always);