`MultiFab.len()` #1047

Job	Run time
🔄 Update Stub Files / Stubs	4m 3s
🐧 Ubuntu / Clang@14.0 w/ libc++ w/ MPI	9m 50s
🐧 Ubuntu / GNU@10.5 Debug	12m 5s
🐧 Ubuntu / GNU@7.5	10m 11s
🐧 Ubuntu / Clang@6.0 w/o MPI	4m 43s
🐧 Ubuntu / CUDA@11.2 GNU@9.4.0	3m 59s
🐧 HIP / ROCm HIP 6.1	9m 41s
🍏 macOS / AppleClang@14.0 w/o MPI	4m 36s
🔎 CodeQL / Analyze (python)	3m 36s
🐧 Intel / ICC	14m 51s
🐧 Intel / oneAPI SYCL 3D	10m 13s
🔎 CodeQL / Analyze (cpp)	36m 44s
🐧 Intel / ICPX	8m 5s
🪟 Windows / Clang w/o MPI Shared Debug	24m 55s
🪟 Windows / MSVC w/o MPI Static Release	1h 24m 56s
	4h 2m 28s

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