Start addressing some wasm32-unknown-unknown errors for matrix-sdk-ui crate

[zzorba]

This change consists mostly of type-wrangling to support building the matrix-sdk-ui crate for wasm32-unknown-unknown. It is a step along the way of (ideally) supporting wasm32 throughout the entire project. The matrix-sdk-ui packages is not yet compiling due to some blocking issues, but these changes should be able to be landed now as a step towards that goal.

The changes consist of one of two main types.

1. Promoting some types related to futures to the matrix-sdk-base, where an existing 'polyfill' of sorts for Futures already existed. This includes stuff around 'boxing' futures and aborting them.
2. Switching to use the matrix-sdk-base spawn instead of tokio::spawn. On non-wasm32 platforms this should be a noop.

• [ ] Public API changes documented in changelogs (optional)

Signed-off-by: Daniel Salinas

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 42.85714% with 12 lines in your changes missing coverage. Please review.

Project coverage is 84.84%. Comparing base (8865e2f) to head (2592405).

Files with missing lines	Patch %	Lines
crates/matrix-sdk-common/src/executor.rs	56.25%	7 Missing :warning:
crates/matrix-sdk-base/src/store/observable_map.rs	0.00%	4 Missing :warning:
crates/matrix-sdk/src/sliding_sync/mod.rs	0.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4122      +/-   ##
==========================================
- Coverage   84.89%   84.84%   -0.05%     
==========================================
  Files         272      271       -1     
  Lines       29167    29179      +12     
==========================================
- Hits        24761    24758       -3     
- Misses       4406     4421      +15     

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[zzorba]

With an additional change to relax the use of Send+Sync in the eyeball package, I have the rest of this crate building locally.

remaining.patch

[zzorba]

Afraid I'm going to have to close this for now, will revisit in the new year when we have time to focus on this effort again.

[maan2003]

I rebased my patches and bunch of new changes: https://github.com/matrix-org/matrix-rust-sdk/compare/main...maan2003:matrix-rust-sdk:push-rumyppqlqkkq?expand=0

But I don't have the energy to go through review :/