Sets the private key for a server certificate or client certificate.
A secure connection using this SecurityContext will use this key with
the server or client certificate to sign and decrypt messages.
keyFile
is a PEM file containing an encrypted
private key, encrypted with password
. An unencrypted file can be
used, but this is not usual.
The function returns a Future that completes when the key has been added to the context.
Source
Future usePrivateKey(String keyFile, {String password});