Generally attempt to simplify the Swift runtime (without thinking too much about performance) and harden everything
Avoid CFFoundation (e.g. OutputStream.toMemory() didn't seem to be an extensible buffer) and use the copy-on-write Swift arrays as buffers everywhere we can
Avoid pulling big chunk of code for 128-bit integers (not used in Diem anyway)
Try to consistently mark throws public APIs that could throw in the future
Review all integer conversions: by default conversion underflows/overflows crash at runtime which is really nasty
Makes booleans and maps more strict in BCS (covered by the Rust-driven fuzzing tests)
Summary
throwspublic APIs that could throw in the futureTest Plan
new runtime tests in CI