Macro logger_assert 

macro_rules! logger_assert {
    ($log_filter:expr, $cond:expr) => { ... };
    ($log_filter:expr, $cond:expr,) => { ... };
    ($log_filter:expr, $cond:expr, $($arg:tt)+) => { ... };
}

Will log with log_filter and panic when condition not met.

The first argument is LogFilter or KeyFilter, the rest arguments are like core::assert!().

Examples:

use captains_log::*;
let logger = filter::KeyFilter::new("req_id", format!("{:016x}", 123).to_string());
let user_id = Some(111);
logger_assert!(logger, user_id.is_some());
logger_assert!(logger, user_id.is_some(), "user must login");