ActionMailer::Base::DeprecatedHeaderProxy

     # File lib/action_mailer/base.rb, line 450
450:       def initialize(message)
451:         @message = message
452:       end

     # File lib/action_mailer/base.rb, line 454
454:       def []=(key, value)
455:         unless value.is_a?(::String)
456:           ::ActiveSupport::Deprecation.warn("Using a non-String object for a header's value is deprecated. "              "You specified #{value.inspect} (a #{value.class}) for #{key}", caller)
457: 
458:           value = value.to_s
459:         end
460: 
461:         @message[key] = value
462:       end

     # File lib/action_mailer/base.rb, line 465
465:       def headers(hash = {})
466:         hash.each_pair do |k,v|
467:           self[k] = v
468:         end
469:       end

     # File lib/action_mailer/base.rb, line 471
471:       def method_missing(meth, *args, &block)
472:         @message.send(meth, *args, &block)
473:       end