Send Backup tracking issue

[flub]

#4007 has been merged now, but follow up work is needed still to make everything work smoothly:

Core

• calling dc_backup_provider_new twice lacks last error set #4178
  • failing dc_receive_backup() lacks last error set #4186
  • Make sure set_last_error is called for .log_err() #4187 or Explicitly call Context::set_last_error in ffi #4195
• is dc_stop_io() needed before dc_backup_provider_new() or not? #4176
  • Pause I/O in get_backup() #4177
  • feat: Pause IO for BackupProvider #4182
• When BackupProvider is dropped it should be killed #4179
  • feat(imex): Cancel BackupProvider when dropped #4242
• Move to released version of iroh again
  • Move to main branch first: deps(iroh): switch back to iroh main branch #4202
• deal with disabled bcc_self after successful backup-transfer #4183
• Ensure dc_backup_provider_new behaves well when cancelled #4192
• BackupProvider JSON-RPC: make getting QR code easier #4191
  • ref(jsonrpc): Getting backup provider QR code now blocks #4198
• Overlapping IoPauseGuards do not work #4193
• send backup: fail quickly on insufficient storage #4200
• Unsafe spawn in dc_receive_backup #4204
• Connect faster
  • feat(imex) Connect to all provider addresses concurrently #4240

Android

• add multi-device-setup deltachat/deltachat-android#2493

iOS

• add multi-device-setup deltachat/deltachat-ios#1822

Desktop

• networked multidevice setup deltachat/deltachat-desktop#3150

Other 3rd party dependencies

• New quinn (actually only quinn-udp and its dependency quinn-proto) release with:
  • Fallback to not using ECN if IP_TOS is not supported quinn-rs/quinn#1516
  • Implement fallback for sendmmsg and recvmmsg quinn-rs/quinn#1504
• New default-net
  • feat: Android compatibility shellrow/netdev#22

Status

(initial version from #4007 (comment))

tries on real devices and simulators/emulators (everyone, please update this post as needed)

• ✅ working: iOS or repl ➡️ iOS or repl
• ❌ failing: Android Emulator, API 33 ➡️ iOS - log
• ✅ failing working: Android MogoG/API25/32bit ➡️ iOS - log - fix
• ✅ failing working: iOS ➡️ Android MogoG/API25/32bit - log - fix
• ✅ Android ➡️ Win 11 repl - works, but need to disable firewall on Win 11 in advance, there is no prompt from the OS, it silently blocks incoming connections by default
• for ios, both works, simulator as well as real device

[link2xt]

Let's close this, it is done and current task is #4546