Feature request: locally generated session & key #67

I have a use-case where I am trying to debug CI pipelines that build Docker containers. The Docker containers are being built simultaneously as arm64 as well as x86 using BuildKit.

To that end, adding a tunshell command to the build script ends up running the command twice: once in an arm64 environment and one in an x86 environment. This causes one of the commands to fail with "Error occurred: Connection has already been joined by another host". This kills the BuildKit command.

Is it possible to build a feature where the session & key are generated on demand by the client, with these parameters printed to stdout?