class HTTParty::HeadersProcessor

def call
  return unless options[:headers]
  options[:headers] = headers.merge(options[:headers]) if headers.any?
  options[:headers] = Utils.stringify_keys(process_dynamic_headers)
end

def initialize(headers, options)
  @headers = headers
  @options = options
end

def process_dynamic_headers
  options[:headers].each_with_object({}) do |header, processed_headers|
    key, value = header
    processed_headers[key] = if value.respond_to?(:call)
                               value.arity == 0 ? value.call : value.call(options)
                             else
                               value
                             end
  end
end