Not quite. The futures crate, version 0.1, contained a definition of the `Future` trait and a bunch of the combinator methods. This was iterated on a lot. Event

Not quite. The futures crate, version 0.1, contained a definition of the `Future` trait and a bunch of the combinator methods. This was iterated on a lot. Eventually, the bare minimum traits were added to the standard library. The futures crate, version 0.3 (released under the name `futures-preview` right now with an alpha version number), contains the helper methods for the standard library's trait.