# File lib/faraday/request/multipart.rb, line 46
    def process_params(params, prefix = nil, pieces = nil, &block)
      params.inject(pieces || []) do |all, (key, value)|
        key = "#{prefix}[#{key}]" if prefix

        case value
        when Array
          values = value.inject([]) { |a,v| a << [nil, v] }
          process_params(values, key, all, &block)
        when Hash
          process_params(value, key, all, &block)
        else
          all << block.call(key, value)
        end
      end
    end