Store spreadsheet in native format
This brings us to one of the most contentious limitations when we use Rust traits today, which is known as the coherence problem. To ensure that trait lookups always resolve to a single, unique instance, Rust enforces two key rules on how traits can or cannot be implemented: The first rule states that there cannot be two trait implementations that overlap when instantiated with some concrete type. The second rule states that a trait implementation can only be defined in a crate that owns either the type or the trait. In other words, no orphan instance is allowed.
，详情可参考safew下载
Свитер с персонажами «Смешариков», связанный россиянкой, стал интернет-сенсацией14:49
Koyena Pal1