Version 4.0.0

⚠️ Breaking Changes

NOTE: These changes may not affect you if you were only using the higher level
functions exposed from this library, which is quite a common scenario.

• #11 The request function has been removed in favour of Request and
  sendRequest.
• #11 The return value from retrieve, sendJson, and sendForm was changed
  from a Future of an IncommingMessage to a Future of the new Response type.
  If you were using bufferResponse or autoBufferResponse, then you don't
  have to change your code, because:
• #11 The bufferResponse and autoBufferResponse now take a Response
  instead of an IncomingMessage.

✨ New Features

• #11 A new sendRequest function has taken the place of the request function.
  This function takes its request options as a single argument.
• #11 A new Request type (and constructor) was added. This is used to
  represent an HTTP request in a pure way. Values of this type are used as input
  for the sendRequest function.
• #11 A new Response type (and constructor) was added. This is used to
  represent a request/response pair.
• #11 A matchStatus function was added for matching against a Response based
  on the response status code.
• #11 Various utility functions for building automatic redirection chains were
  added. These are redirectAnyRequest, redirectIfGetMethod,
  redirectUsingGetMethod, retryWithoutCondition, defaultRedirectionPolicy,
  aggressiveRedirectionPolicy, followRedirectsWith, and followRedirects.
• #11 New functions were added to complement the existing response-consumption
  functions like bufferResponse and autoBufferResponse with versions that
  take an IncomingMessage directly. These are bufferMessage and
  autoBufferMessage respectively.