Type Alias LogLevelSetter 

pub type LogLevelSetter = Box<dyn Fn(LogLevel) -> Result<LogLevelApply> + Send + Sync + 'static>;

Closure that swaps the live EnvFilter to one matching level.

Boxed so the runtime can hold it without naming the (large, layered) concrete subscriber type that tracing_subscriber::reload::Handle is generic over. Returning anyhow::Result lets the closure surface filter-parse failures from the new directive string; the LogLevelApply says whether the level was installed at all.

Aliased Type

pub struct LogLevelSetter(/* private fields */);