Need support for generic terminated arrays.

[j3pic]

LISP-BINARY can handle terminated byte buffers and terminated strings, but it's also common in binary formats to have lists of complex structures terminated by some byte sequence. The byte sequence is often of a length that cleanly fits in all or a subset of the fields in the element structure.

For example: kaitai-io/kaitai_struct#445

Such data can currently be read/written using a custom type specifier.