class Grape::Request

def build_headers

two-arg block receives `k`/`v` directly and allocates nothing extra.
`k, v` pair would be boxed into a throwaway Array on every header. A
`with_object` can only pass the block one value plus the memo, so the
Uses a plain `each_header` block instead of `each_header.with_object`: 
def build_headers
  headers = Grape::Util::Header.new
  each_header do |k, v|
    next unless k.start_with? 'HTTP_'
    transformed_header = KNOWN_HEADERS.fetch(k) { -k[5..].tr('_', '-').downcase }
    headers[transformed_header] = v
  end
  headers
end

def cookies 

def cookies
  @cookies ||= Grape::Cookies.new(rack_cookies)
end

def cookies?

touched on the request.
and the Grape::Cookies allocation it triggers, when no cookie was
written this request). Lets the endpoint skip response-cookie flushing,
True once the cookie jar has been materialized (a cookie was read or 
def cookies?
  !@cookies.nil?
end

def headers 

def headers
  @headers ||= build_headers
end

def initialize(env, build_params_with: nil) 

def initialize(env, build_params_with: nil)
  super(env)
  @params_builder = Grape::ParamsBuilder.params_builder_for(build_params_with || Grape.config.param_builder)
end

def make_params 

def make_params
  params = @params_builder.call(rack_params)
  routing_args = env[Grape::Env::GRAPE_ROUTING_ARGS]
  filtered = routing_args&.except(:version, :route_info)
  return params if filtered.blank?
  params.deep_merge!(filtered)
rescue *Grape::RACK_ERRORS
  raise Grape::Exceptions::RequestError
end

def params 

def params
  @params ||= make_params
end