How to garbage collect a DistributedArray for sure?

General Usage
1

Let’s say I create a DistributedArray but then reassign the variable to a new one:

using Distributed
addprocs(1)

using DistributedArrays, LinearAlgebra

da = DArray([@spawnat wid LinearAlgebra.ones(div(1024^3, 8)) for wid in procs()])
# Total memory size should be 2GB

da = DArray([@spawnat wid LinearAlgebra.ones(div(1024^3, 8)) for wid in procs()])

Even if I run @everywhere GC.gc() a few times, the first array is still not garbage collected.
How do I deallocate the first array for sure?

What if a DistributedArray is contained as a field inside some struct: how do I make sure that this array is deallocated when the struct is garbage collected?