Elixir lacks the fine grain control for optimizing I/O which Go provides. Moreover, a bit torrent client requires CPU intensive hash verification, encryption/decryption, and data compression/decompression which will greatly slow down Elixir. You can build a connector to Rust or instead of using slow abstraction layers you can build the thing in Rust if you have the skills.

Rather then tell me, you are going to have to build a bit torrent client in Elixir and show me. Otherwise, after my years experience working with an Elixir team, I don't believe you.