Function EmitOTLPSpan 

pub fn EmitOTLPSpan(
    Name: &str,
    StartNano: u64,
    EndNano: u64,
    Attributes: &[(&str, &str)],
)

Emit an OTLP span to the local collector (Jaeger at 127.0.0.1:4318). Fire-and-forget on a background thread. Stops trying after first failure.