Macro tracing_core::metadata

macro_rules! metadata {
    (name : $name : expr, target : $target : expr, level : $level : expr, fields :
 $fields : expr, callsite : $callsite : expr, kind : $kind : expr) => { ... };
    (name : $name : expr, target : $target : expr, level : $level : expr, fields :
 $fields : expr, callsite : $callsite : expr, kind : $kind : expr,) => { ... };
}

Statically constructs new span metadata.

/// For example:

use tracing_core::metadata::{Kind, Level, Metadata};
static FOO_CALLSITE: MyCallsite = MyCallsite {
    // ...
};

static FOO_METADATA: Metadata = metadata!{
    name: "foo",
    target: module_path!(),
    level: Level::DEBUG,
    fields: &["bar", "baz"],
    callsite: &FOO_CALLSITE,
    kind: Kind::SPAN,
};