Function is_enabled 

pub fn is_enabled(level: Level, target: &str) -> bool

Returns whether logging is enabled at the given level for the given target.

This is useful for conditionally computing expensive log message data:

use fastmcp_core::logging::{is_enabled, Level, targets};

if is_enabled(Level::Debug, targets::HANDLER) {
    let stats = compute_expensive_stats();
    debug!(target: targets::HANDLER, "Handler stats: {:?}", stats);
}