[io] Turn on async prefetching by default.

[Axel-Naumann]

This Pull request:

Changes or fixes:

Checklist:

• tested changes locally
• updated the docs (if necessary)

This PR fixes #

[phsft-bot]

Starting build on ROOT-debian10-i386/soversion, ROOT-performance-centos8-multicore/cxx17, ROOT-ubuntu18.04/nortcxxmod, ROOT-ubuntu2004/python3, mac1015/cxx17, mac11/cxx14, windows10/cxx14
How to customize builds

[phsft-bot]

Build failed on windows10/cxx14.
Running on null:C:\build\workspace\root-pullrequests-build
See console output.

Failing tests:

• projectroot.tmva.tmva.test.gtest_tmva_tmva_test_rreader

[Axel-Naumann]

@phsft-bot build just on windows10/cxx14

[phsft-bot]

Starting build on windows10/cxx14
How to customize builds

[phsft-bot]

Build failed on windows10/cxx14.
Running on null:C:\build\workspace\root-pullrequests-build
See console output.

Failing tests:

• projectroot.tmva.tmva.test.gtest_tmva_tmva_test_rreader

[phsft-bot]

Starting build on ROOT-performance-centos8-multicore/soversion, ROOT-ubuntu2204/nortcxxmod, ROOT-ubuntu2004/python3, mac11/noimt, mac12arm/cxx20, windows10/default
How to customize builds

[phsft-bot]

Build failed on ROOT-ubuntu2204/nortcxxmod.
Running on root-ubuntu-2204-1.cern.ch:/home/sftnight/build/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.test.test_stressgraphics_interpreted
• projectroot.tmva.pymva.test.gtest_tmva_pymva_test_TestRModelParserPyTorch

[phsft-bot]

Build failed on ROOT-performance-centos8-multicore/soversion.
Running on olbdw-01.cern.ch:/data/sftnight/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.test.test_stressgraphics
• projectroot.test.test_stressgraphics_interpreted

[phsft-bot]

Build failed on ROOT-ubuntu2004/python3.
Running on root-ubuntu-2004-3.cern.ch:/home/sftnight/build/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.test.test_stressgraphics_interpreted

[phsft-bot]

Build failed on windows10/default.
Running on null:C:\build\workspace\root-pullrequests-build
See console output.

Failing tests:

• projectroot.tmva.tmva.test.gtest_tmva_tmva_test_rreader

[github-actions]

Test Results

       10 files         10 suites   1d 16h 0m 7s ⏱️
  2 482 tests      514 ✔️   0 💤 1 968 ❌
23 761 runs  19 906 ✔️ 82 💤 3 773 ❌

For more details on these failures, see this check.

Results for commit 13d57dc.