resize!, append! not defined

[mtfishman]

I didn't see an issue for this. I see that resize! isn't defined for MtlVector:

julia> using Metal

julia> v = mtl(randn(10))
10-element MtlVector{Float32, Metal.MTL.MTLResourceStorageModePrivate}:
  0.7318981
  1.1954936
 -0.34666944
 -1.3239378
  0.2817273
  0.04914088
 -0.017454434
  0.076685436
  1.2588097
  0.7811673

julia> resize!(v, 12)
ERROR: MethodError: no method matching resize!(::MtlVector{Float32, Metal.MTL.MTLResourceStorageModePrivate}, ::Int64)

Closest candidates are:
  resize!(::SparseArrays.ReadOnly, ::Any)
   @ SparseArrays ~/.julia/juliaup/julia-1.10.0+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/SparseArrays/src/readonly.jl:33
  resize!(::SparseArrays.UMFPACK.UmfpackWS, ::Any, ::Bool; expand_only)
   @ SparseArrays ~/.julia/juliaup/julia-1.10.0+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/SparseArrays/src/solvers/umfpack.jl:214
  resize!(::BitVector, ::Integer)
   @ Base bitarray.jl:814
  ...

Stacktrace:
 [1] top-level scope
   @ REPL[8]:1
 [2] top-level scope
   @ ~/.julia/packages/Metal/lnkVP/src/initialization.jl:57

which means functions that rely on it like append! don't work:

julia> append!(v, mtl([1, 2, 3]))
ERROR: MethodError: no method matching resize!(::MtlVector{Float32, Metal.MTL.MTLResourceStorageModePrivate}, ::Int64)

Closest candidates are:
  resize!(::SparseArrays.ReadOnly, ::Any)
   @ SparseArrays ~/.julia/juliaup/julia-1.10.0+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/SparseArrays/src/readonly.jl:33
  resize!(::SparseArrays.UMFPACK.UmfpackWS, ::Any, ::Bool; expand_only)
   @ SparseArrays ~/.julia/juliaup/julia-1.10.0+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/SparseArrays/src/solvers/umfpack.jl:214
  resize!(::BitVector, ::Integer)
   @ Base bitarray.jl:814
  ...

Stacktrace:
 [1] _append!(a::MtlVector{…}, ::Base.HasShape{…}, iter::MtlVector{…})
   @ Base ./array.jl:1196
 [2] append!(a::MtlVector{…}, iter::MtlVector{…})
   @ Base ./array.jl:1187
 [3] top-level scope
   @ REPL[9]:1
 [4] top-level scope
   @ ~/.julia/packages/Metal/lnkVP/src/initialization.jl:57
Some type information was truncated. Use `show(err)` to see complete types.

This causes issues for generic in-place code that relies on resize!/append! to be defined for AbstractVector.

Version information:

julia> versioninfo()
Julia Version 1.10.0
Commit 3120989f39b (2023-12-25 18:01 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin22.4.0)
  CPU: 10 × Apple M1 Max
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, apple-m1)
  Threads: 1 on 8 virtual cores

(Metal.jl) pkg> st
Status `~/Simons Foundation Dropbox/Matthew Fishman/Documents/workdir/temp_julia_project/Metal.jl/Project.toml`
  [dde4c033] Metal v0.5.1

Please let me know if there is a simple workaround or low level definition I could use, and if so I'm happy to make a PR.

[maleadt]

With the current design, there's no easy way to implement resize or append efficiently, so you could copy the CUDA.jl impl: https://github.com/JuliaGPU/CUDA.jl/blob/1ea0a8bd64b0d79174082fcd43682e2881ba6f77/src/array.jl#L864-L902