# File lib/ftw/http/headers.rb, line 76
  def remove(field, value=nil)
    field = field.downcase
    if value.nil?
      # no value, given, remove the entire field.
      @headers.delete(field)
    else
      field_value = @headers[field]
      if field_value.is_a?(Array)
        # remove a specific value
        field_value.delete(value)
        # Down to a String again if there's only one value.
        if field_value.size == 1
          set(field, field_value.first)
        end
      else
        # Remove this field if the value matches
        if field_value == value
          remove(field)
        end
      end
    end
  end