If the slice is immutable, assumes the slice is a literal or
GC-allocated and does NOT copy it internally.
Warning: Subsequently deallocating s will cause the RCXString
to dangle. If the slice has const or mutable characters, creates
and manages a copy internally.
Construct a RCXString from a slice s.
If the slice is immutable, assumes the slice is a literal or GC-allocated and does NOT copy it internally.
Warning: Subsequently deallocating s will cause the RCXString to dangle. If the slice has const or mutable characters, creates and manages a copy internally.