Function base::descriptor_reflection::set_descriptor_src  
source ยท fn set_descriptor_src(
    descriptors: Vec<Option<SafeDescriptor>>,
) -> Result<(), &'static str>Expand description
Sets the thread local storage of descriptors for deserialization. Fails if this was already
called without a call to take_descriptor_src on this thread.
This is given as a collection of Option so that unused descriptors can be returned.