### What this PR does / why we need it?
Conditional Import for Mooncake: The import of
mooncake.engine.TransferEngine was moved into a try-except block within
the GlobalTE class's constructor. This ensures that mooncake is only
imported when needed and provides a clear error message with
installation instructions if it's missing.
### Does this PR introduce _any_ user-facing change?
The error message "ascend_transport.so: cannot open shared object file:
No such file or directory" in the CI is fixed to ensure the normal
running of the CI.
- vLLM version: v0.17.0
- vLLM main:
4034c3d32e
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Signed-off-by: 房建伟 <fangjianwei@fangjianweideMacBook-Air.local>
Co-authored-by: 房建伟 <fangjianwei@fangjianweideMacBook-Air.local>