message: Ensure the output length of trace message IDs is always 16
diff: @@ -23,7 +23,7 @@ struct TraceId<'a>(&'a [u8]);
  impl<'a> Display for TraceId<'a> {
  fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
  - write!(f, "{:x}", hash::hash(self.0))
  + f.write_str(&format!("{:x}", hash::hash(self.0))[..16])
  }
  }
  @@ -96,3 +96,17 @@ where
  F::deserialize(projection, src)
  }
  }
  +
  +#[cfg(test)]
  +mod tests {
  + use super::TraceId;
  +
  + #[test]
  + fn trace_id_has_16_character() {
  + let data = Vec::new();
  +
  + let output = format!("{}", TraceId(&data));
  +
  + assert_eq!(output.len(), 16);
  + }
  +}
  