Implement an interface for Distributed-like libraries

[JamesWrigley]

This moves support for Distributed into a package extension and adds an interface for other distributed worker libraries (i.e. DistributedNext.jl) to use to support Revise for their workers. Admittedly the interface is quite... clunky... so I'm open to other ideas. This also required bumping the minimum Julia version to 1.9 to use package extensions.

As a bonus the load times are slightly improved:

# v3.6.4
julia> @time_imports using Revise
      2.7 ms  OrderedCollections
      0.2 ms  UUIDs
      3.8 ms  CodeTracking
               ┌ 0.2 ms JuliaInterpreter.__init__() 
    136.9 ms  JuliaInterpreter 72.95% compilation time
     35.6 ms  LoweredCodeUtils
      0.7 ms  Serialization
               ┌ 0.0 ms Distributed.__init__() 
     31.7 ms  Distributed 71.09% compilation time
               ┌ 0.0 ms NetworkOptions.__init__() 
      2.2 ms  NetworkOptions
      0.4 ms  Printf
               ┌ 0.2 ms MbedTLS_jll.__init__() 
      2.4 ms  MbedTLS_jll
               ┌ 0.1 ms LibSSH2_jll.__init__() 
      2.1 ms  LibSSH2_jll
               ┌ 0.1 ms LibGit2_jll.__init__() 
      2.0 ms  LibGit2_jll
      7.5 ms  LibGit2
               ┌ 0.1 ms Revise.__init__() 
     79.2 ms  Revise

# This PR
julia> @time_imports using Revise
      3.3 ms  OrderedCollections
      3.4 ms  CodeTracking
               ┌ 0.2 ms JuliaInterpreter.__init__() 
    145.1 ms  JuliaInterpreter 73.80% compilation time
     36.3 ms  LoweredCodeUtils
               ┌ 0.1 ms Revise.__init__() 
     80.9 ms  Revise

[timholy]

I'm strongly supportive of anything that reduces dependency on Distributed, especially if the replacements are less vulnerable to invalidations. The overall design of this PR seems OK.

[timholy]

Thanks! Coming out momentarily in Revise 3.7.0.

[affans]

How will this work? Right now, I basically do

using Revise
includet("main.jl")

with main.jl as follows

using Distributed 
addprocs(2, exeflags="--project=.") # for local usage
# if running Revise, all worker processes will be updated with new code
@everywhere using Revise
@everywhere includet("model.jl")

and now if I update model.jl, the code is updated on all workers.

Does this workflow need to be changed?

[JamesWrigley]

No, the behaviour should be identical to previous versions. The only change in the PR is to make loading Distributed optional and allow support for other libraries to hook into Revise for their workers.

[timholy]

@affans , Distributed badly needs re-engineering. This should make it easier to update or replace it.