Speed problem in emacs source kit-lsp

I'm using sourcekit-lsp in Emacs. I have no errors while using it but too slow to use it. sometimes stop, it may be doing stuff behind it like network communication. And the other problem is that I cannot use UIKit module. when I use company-lsp, it shows auto-completion list, but I cannot find UIKit module. How can I do?

I have no errors while using it but too slow to use it. sometimes stop, it may be doing stuff behind it like network communication.

Could you file a bug at bugs.swift.org and attach a sample or spindump taken while this is happening? You can find these tools in Activity Monitor, select the sourcekit-lsp process and look in the gear menu.

And the other problem is that I cannot use UIKit module.

Is this a swiftpm pacakge? How are you building your project?