Cargo Features

The dbos crate's Cargo features:

Feature	Default	What it turns on
engine	yes	The durable execution engine: the lifecycle, workflows, steps, queues, messaging, schedules and the client. Without it, only the system-database layer (dbos::sysdb) is left.
macros	yes	select_step!, the durable race. It is a procedural macro, so it adds syn and quote to the build. Implies engine.
runtime-tokio	yes	Runs DBOS's background tasks and timers on Tokio.
runtime-smol	no	Runs them on smol.
runtime-async-global-executor	no	Runs them on async-global-executor.

At least one runtime feature is required. Several may be enabled; DBOS then picks one when it runs, as Async Runtimes describes.

To use smol instead of Tokio:

[dependencies]
dbos = { version = "0.6", default-features = false, features = ["engine", "macros", "runtime-smol"] }