message: Generate Default derive for params
diff: @@ -696,9 +696,20 @@ fn gen_impl_object(meta: &Metadata, object: &str) -> String {
  Some(some) => some.as_slice(),
  None => &[],
  };
  +
  + // Derive Default when no param is required
  + let can_derive_default =
  + parameters.iter().all(|param| param["required"].as_bool() != Some(true));
  +
  out.push('\n');
  out.push_str(&format!("/// The parameters for `{}::{}`.\n", struct_name, params.method));
  +
  + if can_derive_default {
  + out.push_str("#[derive(Clone, Debug, Serialize, Default)]\n");
  + } else {
  out.push_str("#[derive(Clone, Debug, Serialize)]\n");
  + }
  +
  out.push_str("pub struct ");
  out.push_str(&params.rust_type);
  out.push_str("<'a> {\n");
  