[BUG] - SFTP Performance Issues

[probgoblin]

Description

When using a "get" command from the sftp CLI, I download a ~2GB file in a little under 3 minutes, averaging ~12MB/s. Downloading the same file from the same server over the same network using termscp takes several hours with an average speed of under 200kb/s.

Steps to reproduce

I am able to reproduce this on multiple machines (using Bazzite) with termscp installed via Brew.

Expected behavior

I would expect download speeds to be roughly on par with sftp.

Environment

• OS: Bazzite 43.x (has persisted across all releases since I started using termscp in December of 2025)
• Architecture [Arm, x86_64, ...]: x86_64
• Rust version: Not installed, but homebrew builds against 1.94.0
• termscp version: 0.19.1
• Protocol used: sftp
• Remote server version and name: SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.5

Log

No relevant log as process works, just slowly.

Additional information

No additional information to report.

[veeso]

I know there was a similiar issue with libssh2, but since 0.19 I switched to libssh, so I don't know that whether the same issue exists on libssh, or that server in particular has huge issues with libssh for some reason.

It would be interesting if you could try to use SCP instead of SFTP.

[probgoblin]

Trying to use SCP results in:
Could not download file: File transfer error: failed to open file (protocol error (Invalid SCP header: not enough parts))

Unfortunately, I don't manage that server so I can't try changing anything on its end.

[veeso]

I think this should be fixed with 52dd762 (1.0.0)