Indicates that structure can be initialize from environment variables.
Creates empty context and calls
fn with_context(context: Context<Self>) -> Result<Self, Error> where
Initialize structure from environment variable from the passed context.
By default calls
parse method. It works for a basic type like number or string.
The method is redefined for a sctructure with
#[derive(Yasec). In that case
the method pick every field type and calls the method for the type.
Parses an environment variable value. It sould be implemented if an object is leaf of a configuration structure.