Macro log_trace 

macro_rules! log_trace {
    ($ctx:expr, $msg:expr) => { ... };
    ($ctx:expr, $msg:expr, $($key:ident => $value:expr),+ $(,)?) => { ... };
    ($ctx:expr, $fmt:expr, $($arg:tt)*) => { ... };
}

Logs a message at the TRACE level with request context.

Returns a LogEntry that can be emitted or inspected. For zero-overhead logging, use RequestLogger.

Example

log_trace!(ctx, "Entering function");
log_trace!(ctx, "Processing item {}", item_id);
log_trace!(ctx, "With fields", key => value, another => thing);