def to_h
      h = {}
      each do |header|
        h[header.key] = header.value
      end
      h
    end
def to_h
      h = {}
      each do |header|
        h[header.key] = header.value
      end
      h
    end
Returns a hash from the headers in the set, where keys are
 formed from #key and values from #value for each header.

     rh_string = Redhead::String["foo: bar\nbaz: baaaaz\n\nstring"]
     rh_string.headers.to_h

     # A Hash instance:
     #=> { foo: "bar", baz: "baaaaz" }