message: pnet_macro: make minimum_packet_size() const.
diff: @@ -991,7 +991,7 @@ fn generate_packet_impl(cx: &mut GenContext,
  /// The minimum size (in bytes) a packet of this type can be. It's based on the total size
  /// of the fixed-size fields.
  #[inline]
  - pub fn minimum_packet_size() -> usize {{
  + pub const fn minimum_packet_size() -> usize {{
  {byte_size}
  }}
  