perf-stream-consume: use the source repository config when applying This might contains critical configuration for the benchmark, like enabling of extensions like narrow.

unbundle: move most of the logic on cmdutil to help debug::unbundle reuse This make sure `hg debug::unbundle` focus on the core logic.

postincoming: move to cmdutil This looks like a good place for it to live.

postincoming: avoid computing branchhead if no report will be posted This otherwise defeat some of the branch v3 optimization.

streamclone: stop listing files for entries that have no volatile files This will save a lot of python related time. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) prev-change: 20.88 seconds (-40%) prev-change: 14.22 seconds (-60%) this-change: 11.58 seconds (-67% from baseline; -18% from prev)

stream-clone: disable gc for the initial section for the v3 format The number of small container created turn Python in a gc-frenzy that seriously impact performance. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) prev-change: 20.88 seconds (-40%) this-change: 14.22 seconds (-60% from baseline; -31% from prev)

stream-clone: disable gc for `_entries_walk` duration The number of small container created turn Python in a gc-frenzy that seriously impact performance. This significantly boost performance. The following number comes from a large private repository using perf::stream-locked-section: base-line: 35.04 seconds prev-change: 24.51 seconds (-30%) this-change: 20.88 seconds (-40% from baseline; -15% from previous changes)

nocg: make the utility work are both a decorator and context manager In some case, the context manager version will be simpler.