Destructors

Unlike constructors, destructors in Rust have a special status: they are added by implementing Drop for a type, and they are automatically invoked as values go out of scope.

[FIXME] This section needs to be expanded.

Destructors should not fail. [FIXME: needs RFC]

Destructors are executed on task failure, and in that context a failing destructor causes the program to abort.

Instead of failing in a destructor, provide a separate method for checking for clean teardown, e.g. a close method, that returns a Result to signal problems.

Destructors should not block. [FIXME: needs RFC]

Similarly, destructors should not invoke blocking operations, which can make debugging much more difficult. Again, consider providing a separate method for preparing for an infallible, nonblocking teardown.