Example 1, stuck

# After execution gets stuck, sending `schedule(t, nothing, error=true)` to the task: 
Stacktrace:
  [1] try_yieldto(undo::typeof(Base.ensure_rescheduled))
    @ Base ./task.jl:777
  [2] wait()
    @ Base ./task.jl:837
  [3] wait(c::Base.GenericCondition{ReentrantLock})
    @ Base ./condition.jl:123
  [4] wait(e::Base.Event)
    @ Base ./lock.jl:366
  [5] nonblocking_synchronize
    @ ~/.julia/packages/CUDA/0IDh2/lib/cudadrv/stream.jl:160 [inlined]
  [6] macro expansion
    @ ~/.julia/packages/CUDA/0IDh2/src/array.jl:406 [inlined]
  [7] macro expansion
    @ ~/.julia/packages/CUDA/0IDh2/src/state.jl:182 [inlined]
  [8] unsafe_copyto!(dest::Matrix{Float32}, doffs::Int64, src::CUDA.CuArray{Float32, 2, CUDA.Mem.DeviceBuffer}, soffs::Int64, n::Int64)
    @ CUDA ~/.julia/packages/CUDA/0IDh2/src/array.jl:402
  [9] copyto!
    @ ~/.julia/packages/CUDA/0IDh2/src/array.jl:356 [inlined]
 [10] copyto!
    @ ~/.julia/packages/CUDA/0IDh2/src/array.jl:360 [inlined]
 [11] copyto_axcheck!(dest::Matrix{Float32}, src::CUDA.CuArray{Float32, 2, CUDA.Mem.DeviceBuffer})
    @ Base ./abstractarray.jl:1104
 [12] Array
    @ ./array.jl:563 [inlined]
 [13] Array
    @ ./boot.jl:481 [inlined]
 [14] convert
    @ ./array.jl:554 [inlined]
 [15] adapt_storage
    @ ~/.julia/packages/Adapt/hZ1HH/src/arrays.jl:6 [inlined]
 [16] adapt_structure
    @ ~/.julia/packages/Adapt/hZ1HH/src/Adapt.jl:42 [inlined]
 [17] adapt
    @ ~/.julia/packages/Adapt/hZ1HH/src/Adapt.jl:40 [inlined]
 [18] adapt_storage
    @ ~/.julia/packages/Flux/BPPNj/src/functor.jl:75 [inlined]
 [19] adapt_structure
    @ ~/.julia/packages/Adapt/hZ1HH/src/Adapt.jl:42 [inlined]
 [20] adapt
    @ ~/.julia/packages/Adapt/hZ1HH/src/Adapt.jl:40 [inlined]
 [21] #134
    @ ~/.julia/packages/Flux/BPPNj/src/functor.jl:115 [inlined]
 [22] fmap(f::Flux.var"#134#135", x::CUDA.CuArray{Float32, 2, CUDA.Mem.DeviceBuffer}; exclude::typeof(Functors.isleaf), walk::typeof(Functors._default_walk), cache::IdDict{Any, Any})
    @ Functors ~/.julia/packages/Functors/hIysk/src/functor.jl:121
 [23] fmap
    @ ~/.julia/packages/Functors/hIysk/src/functor.jl:120 [inlined]
 [24] cpu(x::CUDA.CuArray{Float32, 2, CUDA.Mem.DeviceBuffer})
    @ Flux ~/.julia/packages/Flux/BPPNj/src/functor.jl:115
 [25] inference(imgs::CUDA.CuArray{Float32, 4, CUDA.Mem.DeviceBuffer})
    @ Main ~/knightvision/piece_recognition/KnightVisionServer/test/test_cuda.jl:16
 [26] (::var"#7#8")()
    @ Main ./threadingconstructs.jl:178