Helper trait to create instances of large structs with default value on heap directly without going through stack.
Similar to the unstable
it semantically doesn't require creating the whole struct on stack then moving to heap,
and thus unlike
it doesn't rely on optimization to eliminate building the struct on stack,
which may still face stack overflow on debug build when creating large struct.
use DefaultBoxed; const BASE: usize = 1024; ; let foo = default_boxed; assert_eq!; assert_eq!; assert_eq!; let foo_arr = ; assert_eq!;