Crate relevant

Defines Relevant type to use in types that requires custom destruction. Crate supports 3 main mechnisms for error reporting:

• “panic” feature makes Relevant panic on drop
• “log” feature uses log crate and Relevant will emit log::error! on drop.
• otherwise Relevant will print into stderr using eprintln! on drop.

“backtrace” feature will add backtrace to the error unless it is reported via panicking. “message” feature will add custom message (specified when value was created) to the error.

Structs

• Relevant
  Values of this type can’t be automatically dropped. If struct or enum has field with type Relevant, it can’t be automatically dropped either. And so considered relevant too. User has to deconstruct such values and call Relevant::dispose. If relevant field is private it means that user has to move value into some public method.