Crate spawns_compat 

spawns-compat provides functions to find async runtimes for spawning task.

It uses linkme to inject these functions to spawns-core. In some platforms, this crate may not be linked to binary finally. So, you may have to speak explicitly about this with extern crate spawns_compat. You could also use it with spawns-core through spawns which does so for you. Besides this, in macOS, you may have to put below to your Cargo.toml.

[profile.dev]
lto = "thin"

See for details:

• https://stackoverflow.com/questions/29403920/whats-the-difference-between-use-and-extern-crate/29404692#29404692
• https://github.com/dtolnay/linkme/issues/31
• https://github.com/dtolnay/linkme/issues/61