• SSH2: fixes relating to delayed global requests (#1271)
• SSH2: setEngine -> setPreferredEngine (#1294)
• SSH2: reset $this->bitmap when the connection fails (#1298)
• SSH2: add ping() method (#1298)
• SSH2: add support for rsa-sha2-256 / rsa-sha2-512 (RFC8332)
• SFTP: make rawlist give same result regardless of stat cache (#1287)
• Hash: save hashed keys for re-use