Requests 0.2

New

• Added a BodyProvider type that can generate the body of a request. This
  replaces the raw body data that was previously provided by a
  RequestConvertible type. A BodyProvider wraps a throwing function that
  generates a RequestBody and updates a Header. Built-in body providers are
  included for:
  • JSON bodies
  • Plain text bodies
  • Stream bodies
  • Raw data bodies
• Added an AuthenticationProvider type that can add authentication credentials
  to the header of a request. An AuthenticationProvider wraps a function that
  updates a Header instance. Built-in authentication providers are included
  for:
  • HTTP Basic authentication.
  • Bearer token authentication.
• Added a setter subscript to the Header type that can set a Field.

API Breaking Changes

• Requests now requires Swift 4.2
• The httpBody property has been removed from the RequestConvertible
  protocol. It is replaced by the bodyProvider property. This will silently
  break existing code.
• Header fields are now backed by a CaseInsensitiveString type instead of a
  String.
• The contentType and accept Fields now accept a MediaType instance
  instead of a string.