message: Made field methods const fns
diff: @@ -12,13 +12,13 @@ pub struct Field(u32);
  impl Field {
  /// Create a new field object for the given FieldId.
  - pub fn from_field_id(field_id: u32) -> Field {
  + pub const fn from_field_id(field_id: u32) -> Field {
  Field(field_id)
  }
  /// Returns a u32 identifying uniquely a field within a schema.
  #[allow(clippy::trivially_copy_pass_by_ref)]
  - pub fn field_id(&self) -> u32 {
  + pub const fn field_id(&self) -> u32 {
  self.0
  }
  }
  