$ java --enable-preview -cp ... RoundTrip     (27.0.1.0.2+1)
== decode a public key, a private key and a certificate
RSA X.509 2048 bits
RSA PKCS#8
CN=localhost issued by CN=pem-api demo CA
== encode them again: the same text openssl wrote, apart from the line terminator
PEMEncoder line terminator is CRLF: true; the openssl file uses LF: true
ok: raw text differs from the file (CRLF vs LF)
ok: public key re-encodes to identical text once CRLF is normalised to LF
ok: private key re-encodes to identical text (LF-normalised)
ok: certificate re-encodes to identical text (LF-normalised)
== encode a key pair that was generated just now
[-----BEGIN PRIVATE KEY-----, -----END PRIVATE KEY-----]
line width of the Base64 body: 64
ok: private scalar survives the round trip
ok: public key survives the round trip
ok: ...but the private key's own encoding is not byte-for-byte the same (the PKCS#8 now carries the public key)
== what does decode(String) with no target class hand back?
rsa-public.pem -> PublicKey RSA
rsa-private-pkcs8.pem -> PrivateKey RSA
ed25519-private.pem -> PrivateKey EdDSA
server.pem -> X509Certificate CN=localhost
rsa-private-encrypted.pem -> EncryptedPrivateKeyInfo PBEWithHmacSHA256AndAES_256
exit=0
