parse_rhs

# File lib/soap/mimemessage.rb, line 78
    def parse_rhs(str)
      a = str.split(/;+\s+/)
      header = Header.new
      header.str = str
      header.root = a.shift
      a.each do |pair|
        if pair =~ /(\w+)\s*=\s*"?([^"]+)"?/
          header[$1.downcase] = $2
        else
          raise RuntimeError.new("unexpected header component: #{pair.inspect}")
        end
      end
      header
    end