参考：https://rust-lang.github.io/api-guidelines/naming.html

    | Item | Convention | | —- | —- |

    | Crates | unclear，大小写不敏感、- 和 _ 被认为是相同的 |

    | Modules | snake_case |

    | Types | UpperCamelCase |

    | Traits | UpperCamelCase |

    | Enum variants | UpperCamelCase |

    | Functions | snake_case |

    | Methods | snake_case |

    | General constructors | new or with_more_details |

    | Conversion constructors | from_some_other_type |

    | Macros | snake_case! |

    | Local variables | snake_case |

    | Statics | SCREAMING_SNAKE_CASE |

    | Constants | SCREAMING_SNAKE_CASE |

    | Type parameters | concise UpperCamelCase, usually single uppercase letter: T |

    | Lifetimes | short lowercase, usually a single letter: 'a, 'de, 'src |

    | Features | unclear but see C-FEATURE |

    In UpperCamelCase, acronyms and contractions of compound words count as one word: use Uuid rather than UUID, Usize rather than USize or Stdin rather than StdIn.
    In snake_case, acronyms and contractions are lower-cased: is_xid_start.