| Opaque data structured that holds a parsed
| ECDSA signature, supporting pubkey recovery.
|
| The exact representation of data inside is
| implementation defined and not guaranteed to
| be portable between different platforms or
| versions. It is however guaranteed to be 65
| bytes in size, and can be safely copied/moved.
|
| If you need to convert to a format suitable
| for storage or transmission, use the
| ecdsa_signature_serialize_* and
| ecdsa_signature_parse_* functions.
|
| Furthermore, it is guaranteed that identical
| signatures (including their recoverability)
| will have identical representation, so they
| can be memcmp’ed.