By enabling Interact for a program such as Alacritty, we can probe and modify its state while it runs (for example, modify the cursor's position from the Interact prompt).

The changes in Alacritty do the following:

• Add an invocation of the Interact prompt.
• Add #[derive(Interact)] for a small portion of the types.
• Add special Access and Deser deriving for the FairMutex type.

Here is the interactive state it produces:

>>> term
Term {
    grid: Grid {
        cols: Column (80),
        lines: Line (24),
        display_offset: 0,
        scroll_limit: 0,
        max_scroll_limit: 100000
    },
    input_needs_wrap: false,
    next_title: None,
    next_mouse_cursor: None,
    alt_grid: Grid {
        cols: Column (80),
        lines: Line (24),
        display_offset: 0,
        scroll_limit: 0,
        max_scroll_limit: 0
    },
    alt: false,
    cursor: Cursor {
        point: Point { line: Line (5), col: Column (45) },
        template: Cell { c: ' ' },
        charsets: Charsets ([ Ascii, Ascii, Ascii, Ascii ])
    },
    dirty: false,
    next_is_urgent: None,
    cursor_save: Cursor {
        point: Point { line: Line (0), col: Column (0) },
        template: Cell { c: ' ' },
        charsets: Charsets ([ Ascii, Ascii, Ascii, Ascii ])
    },
    cursor_save_alt: Cursor {
        point: Point { line: Line (0), col: Column (0) },
        template: Cell { c: ' ' },
        charsets: Charsets ([ Ascii, Ascii, Ascii, Ascii ])
    },
    semantic_escape_chars: ",│`|:\"\' ()[]{}<>",
    dynamic_title: true,
    tabspaces: 8,
    auto_scroll: false
}