OptionalcaCA certificate(s) for server verification (PEM format). If not provided, uses default system CA.
OptionalcertClient certificate (PEM format).
OptionalkeyClient private key (PEM format).
OptionalpassphrasePassphrase for the private key.
OptionalrejectWhether to reject unauthorised certificates.
TLS options for mTLS authentication. These are passed directly to Node.js HTTP/2 client.