Trait Callback 

pub trait Callback: Send {
    type Output: Send;

    // Required method
    fn call(&mut self, instr: &Instrument, event: &Event) -> Self::Output;
}

Defines the ability for being passed to Instrument::install_handler

Send is required on both the callback and its output because visa invokes handlers on its own thread and the output is delivered to the installing thread through a channel – neither crosses that boundary safely otherwise.

Required Associated Types

type Output: Send

Required Methods

fn call(&mut self, instr: &Instrument, event: &Event) -> Self::Output

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<F, Out> Callback for F

where F: FnMut(&Instrument, &Event) -> Out + Send, Out: Send,

type Output = Out