Macro get_dependency

macro_rules! get_dependency {
    ( $self:ident.$attribute:ident ) => { ... };
    ( $self:ident.$attribute:ident = $builder:expr ) => { ... };
}

Retrieve attribute stored in the builder. If not yet initialized, we instantiate it by calling the associated build function (build_<attribute_name>). If we don’t want to to use the default build function, we can pass an expression that build the value. Usage examples: get_dependency!(self.signer_registerer) get_dependency!(self.signer_registerer = self.build_signer_registerer().await?)