Request): missing or empty metadata fields: description, license. Please see https://doc.rust-lang.org/ cargo/reference/manifest.html for more information on configuring these fields 这个错误是因为我们缺少一些关键信息：关于该 crate 103) }, data: Struct( DataStruct { struct_token: Struct, fields: Unit, semi_token: Some( Semi ) } ) } 示例 20-41: `#[warn(dead_code)]` on by default warning: fields `id` and `thread` are never read --> src/lib.rs:48:5 | 530/562Rust 程序设计语言 简体中文版 47 | struct Worker { | ------ fields in this struct 48 | id: usize