set_fields!

# File actionmailer/lib/action_mailer/old_api.rb, line 230
    def set_fields!(headers, charset) #:nodoc:
      m = @_message
      m.charset = charset
      m.subject  ||= headers.delete(:subject)  if headers[:subject]
      m.to       ||= headers.delete(:to)       if headers[:to]
      m.from     ||= headers.delete(:from)     if headers[:from]
      m.cc       ||= headers.delete(:cc)       if headers[:cc]
      m.bcc      ||= headers.delete(:bcc)      if headers[:bcc]
      m.reply_to ||= headers.delete(:reply_to) if headers[:reply_to]
    end