traceparent header parser

main.rs

/// See https://w3c.github.io/trace-context-binary/#de-serialization-of-traceparent
fn parse_traceparent(bytes: &[u8]) -> Result<SpanContext, &'static str> {
    if bytes.len() != 29 {
        return Err("Invalid traceparent length. Must be 29 bytes.");
    }

    if bytes[0] != 0 {
        return Err("Unsupported traceparent version.");
    }
    if bytes[1] != 0 {
        return Err("Unsupported trace id");
    }
    let trace_id = TraceId::from_slice(&bytes[2..18]);
    if bytes[18] != 1 {
        return Err("Unsupported parent id");
    }
    let parent_id = SpanId::from_slice(&bytes[19..27]);
    if bytes[27] != 2 {
        return Err("Unsupported trace flags");
    }
    let trace_flags = TraceFlags::from_u8(bytes[28]);

    Ok(SpanContext::new(trace_id, parent_id, trace_flags, true,TraceState::default()))
}