Set the value of the specified header. If value is null and the
header, name, had not been previously set, a space will be set
aside for it (useful for setting the order of headers before values
can be obtained for them) otherwise the header will be unset.
Note: If there are multiple headers with the specified field name,
the first instance of the header will be replaced and further
instances will be removed.
Set the value of the specified header. If value is null and the header, name, had not been previously set, a space will be set aside for it (useful for setting the order of headers before values can be obtained for them) otherwise the header will be unset.
Note: If there are multiple headers with the specified field name, the first instance of the header will be replaced and further instances will be removed.