Function read_packet_from_file 

fn read_packet_from_file(path: impl AsRef<Path>) -> Result<Packet, Error>

Reads a single OpenPGP packet from a file.

The file contents may be binary or ASCII-armored.

Errors

Returns an error if

• the file at path cannot be opened for reading,
• the first byte of the file at path cannot be read,
• the file at path is empty,
• or if not exactly one OpenPGP packet is found in the file at path.