def delete(name)
      name = normalize_header name.to_s
      @pile.delete_if { |k, _| k == name }
    end
def delete(name)
      name = normalize_header name.to_s
      @pile.delete_if { |k, _| k == name }
    end
Removes header.

 @param [#to_s] name header name
 @return [void]