class Rack::Lint::Wrapper

def check_early_hints(env)

# with an object which would be valid as the headers of a Rack response.
# The application or any middleware may call the rack.early_hints
#
# === Early Hints
# 
def check_early_hints(env)
  if env[RACK_EARLY_HINTS]
    ##
    ## If <tt>rack.early_hints</tt> is present, it must respond to #call.
    unless env[RACK_EARLY_HINTS].respond_to?(:call)
      raise LintError, "rack.early_hints must respond to call"
    end
    original_callback = env[RACK_EARLY_HINTS]
    env[RACK_EARLY_HINTS] = lambda do |headers|
      ## If <tt>rack.early_hints</tt> is called, it must be called with
      ## valid Rack response headers.
      check_headers(headers)
      original_callback.call(headers)
    end
  end
end