* some fixes to please cargo-spellcheck

* some (not all) fixes for the impl guide

* fix

* Indentation fix.

* Prepare request-response for PoV fetching.

* Drop old PoV distribution.

* WIP: Fetch PoV directly from backing.

* Backing compiles.

* Runtime access and connection management for PoV distribution.

* Get rid of seemingly dead code.

* Implement PoV fetching.

Backing does not yet use it.

* Don't send `ConnectToValidators` for empty list.

* Even better - no need to check over and over again.

* PoV fetching implemented.

+ Typechecks
+ Should work

Missing:

- Guide
- Tests
- Do fallback fetching in case fetching from seconding validator fails.

* Check PoV hash upon reception.

* Implement retry of PoV fetching in backing.

* Avoid pointless validation spawning.

* Add jaeger span to pov requesting.

* Add back tracing.

* Review remarks.

* Whitespace.

* Whitespace again.

* Cleanup + fix tests.

* Log to log target in overseer.

* Fix more tests.

* Don't fail if group cannot be found.

* Simple test for PoV fetcher.

* Handle missing group membership better.

* Add test for retry functionality.

* Fix flaky test.

* Spaces again.

* Guide updates.

* Spaces.

* add AvailableDataFetchingRequest

* rename AvailabilityFetchingRequest to ChunkFetchingRequest

* rename AvailabilityFetchingResponse to Chunk_

* add AvailableDataFetching request

* add available data fetching request to availability recovery message

* remove availability recovery message

* fix

* update network bridge

* port availability recovery to request/response

* use validators.len(), not shuffling

* fix availability recovery tests

* update guide

* Update node/network/availability-recovery/src/lib.rs

Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>

* Update node/network/availability-recovery/src/lib.rs

Co-authored-by: Arkadiy Paronyan <arkady.paronyan@gmail.com>

* remove println

Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
Co-authored-by: Arkadiy Paronyan <arkady.paronyan@gmail.com>

* Introduce collation fetching protocol

also move to mod.rs

* Allow `PeerId`s in requests to network bridge.

* Fix availability distribution tests.

* Move CompressedPoV to primitives.

* Request based collator protocol: validator side

- Missing: tests
- Collator side
- don't connect, if not connected

* Fixes.

* Basic request based collator side.

* Minor fix on collator side.

* Don't connect in requests in collation protocol.

Also some cleanup.

* Fix PoV distribution

* Bump substrate

* Add back metrics + whitespace fixes.

* Add back missing spans.

* More cleanup.

* Guide update.

* Fix tests

* Handle results in tests.

* Fix weird compilation issue.

* Add missing )

* Get rid of dead code.

* Get rid of redundant import.

* Fix runtime build.

* Cleanup.

* Fix wasm build.

* Format fixes.

Thanks @andronik !

* Guide update for availability distribution.

* Link fix.

* Hopefully fixed implementers guide build.

* Fix bug and further optimizations in availability distribution

- There was a bug that resulted in only getting one candidate per block
as the candidates were put into the hashmap with the relay block hash as
key. The solution for this is to use the candidate hash and the relay
block hash as key.
- We stored received/sent messages with the candidate hash and chunk
index as key. The candidate hash wasn't required in this case, as the
messages are already stored per candidate.

* Update node/core/bitfield-signing/src/lib.rs

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

* Remove the reverse map

* major refactor of receipts & query_live

* finish refactoring

remove ancestory mapping,

improve relay-parent cleanup & receipts-cache cleanup,
add descriptor to `PerCandidate`

* rename and rewrite query_pending_availability

* add a bunch of consistency tests

* Add some last changes

* xy

* fz

* Make it compile again

* Fix one test

* Fix logging

* Remove some buggy code

* Make tests work again

* Move stuff around

* Remove dbg

* Remove state from test_harness

* More refactor and new test

* New test and fixes

* Move metric

* Remove "duplicated code"

* Fix tests

* New test

* Change break to continue

* Update node/core/av-store/src/lib.rs

* Update node/core/av-store/src/lib.rs

* Update node/core/bitfield-signing/src/lib.rs

Co-authored-by: Fedor Sakharov <fedor.sakharov@gmail.com>

* update guide to match live_candidates changes

* add comment

* fix bitfield signing

Co-authored-by: Robert Habermeier <rphmeier@gmail.com>
Co-authored-by: Bernhard Schuster <bernhard@ahoi.io>
Co-authored-by: Fedor Sakharov <fedor.sakharov@gmail.com>

Closes #1237

* rename protocol ID to network capability

* guide: `ProtocolId` -> `NetworkCapability`

* guide: remove `RegisterEventProducer`

* capabilities and expand on underlying network assumptions

* guide: create network.md types file

* guide: network bridge is aware of network messages

* revert changes in code

* Update roadmap/implementers-guide/src/SUMMARY.md

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

* remove references to NetworkCapability

* Update roadmap/implementers-guide/src/types/network.md

Co-authored-by: Sergei Shulepov <sergei@parity.io>

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>
Co-authored-by: Sergei Shulepov <sergei@parity.io>

* Do a small write-up on collation-generation

* preamble to collator protocol

* notes on protocol

* collation-generation: point to collator protocol

* fix missing bracket

* expand on collator protocol wire protocol

* add a couple more sentences

* expand on requests some more

* go higher level

* network bridge: note peerset

* note peer-set = validation for protocols

* add `ConnectToValidators` message

* use ConnectToValidators in collator protocol

* typo

* remove references to sentry nodes

* rename implementor's guide to implementer's guide

* fix typos in more places

* rejig candidate types a bit

* adjust doc

* describe basic PoV distribution

* replace some straggling html links

* address grumbles from review and fix links

* Add mdbook-linkcheck

* Convert todo to not a link

* Fix external glossary link

* Fix various broken links

* Mass replace: s/.html/.md/

* My sloppy attempt to add a gitlab CI check

* adjust to relative links

* additional adjustment to relative link

* link directly to file

* link directly to file

* move old implementers' guide, add skeleton of new

* Split the old implementers' guide into the new one's sections

This is mostly a straightforward copying operation, moving the
appropriate sections from the old guide to the new. However, there
are certain differences between the old text and the new:

- removed horizontal rules between the sections
- promoted headers appropriately within each section
- deleted certain sections which were in the old guide's ToC but
  which were not actually present in the old guide.
- added Peer Set Manager to the new ToC

* remove description headers

It is redundant and unnecessary. Descriptions fall directly under the
top-level header for any given section.

* add stub description of the backing module

* add stub description for the availability module

* add stub description for collators

* add stub description for validity

* add stub description for utility

* highlight TODO and REVIEW comments

* add guide readme describing how to use mdbook

* fix markdownlint lints

* re-title parachains overview

* internal linking for types

* module and subsystem internal links

* .gitignore should have a trailing newline

* node does not have modules, just subsystems