implement incremental encryption using rpgp

[fbrv]

I am currently working on a project that involves encrypting large files. Currently, I wrap a Writer struct into a buffer, and then I encrypt the entire buffer before the writer is dropped. Now, I would like to incrementally encrypt and store inside a file the buffer received to consume less memory. Ideally, the segment size should be configurable, e.g., 16/32 kB. I have searched around and did not find specific examples for achieving this using the rPGP crate. Am I missing something? I only care about the correctness of the encryption; the decryption will be performed by external tools like GPG.