feat: support Set equality comparison in iterableEquals

[ShakyaCsun]

Status

IN DEVELOPMENT

Breaking Changes

YES

Description

Add support for equality comparison between all types of Iterable including Sets to iterableEquals and subsequently all Equatable objects.
Additionally, a propsEquals function which compares the List<Object?> props is added and used in operator == override for Equatable and EquatableMixin in place of iterableEquals to skip the newly added checks and maintain similar performance in the existing benchmarks.

Fixes #196

Impact to Remaining Code Base

This PR will affect:

• Equality checking between non-Set Iterable and Set.
  • returns false instead of throwing AssertionError
• Equality checking between a List and a Iterable of equal elements in same order.
  • returns false instead of true

Benchmarks result from before and after

EmptyEquatable

stat	Before	After
total runs	1 759 499	1 743 908
total time	2.0000 s	2.0000 s
average run	1 μs	1 μs
runs/second	1 000 000	1 000 000
units	100	100
units/second	100 000 000	100 000 000
time per unit	0.0100 μs	0.0100 μs

PrimitiveEquatable

stat	Before	After
total runs	520 591	519 660
total time	2.0000 s	2.0000 s
average run	3 μs	3 μs
runs/second	333 333	333 333
units	100	100
units/second	33 333 333	33 333 333
time per unit	0.0300 μs	0.0300 μs

CollectionEquatable (static, small)

stat	Before	After
total runs	89 451	75 242
total time	2.0000 s	2.0000 s
average run	22 μs	26 μs
runs/second	45 455	38 462
units	100	100
units/second	4 545 455	3 846 154
time per unit	0.2200 μs	0.2600 μs

CollectionEquatable (static, medium)

stat	Before	After
total runs	59 444	67 114
total time	2.0000 s	2.0000 s
average run	33 μs	29 μs
runs/second	30 303	34 483
units	100	100
units/second	3 030 303	3 448 276
time per unit	0.3300 μs	0.2900 μs

CollectionEquatable (static, large)

stat	Before	After
total runs	15 980	32 739
total time	2.0001 s	2.0000 s
average run	125 μs	61 μs
runs/second	8 000.0	16 393
units	100	100
units/second	800 000	1 639 344
time per unit	1.2500 μs	0.6100 μs

CollectionEquatable (dynamic, small)

stat	Before	After
total runs	251 623	223 689
total time	2.0000 s	2.0000 s
average run	7 μs	8 μs
runs/second	142 857	125 000
units	100	100
units/second	14 285 714	12 500 000
time per unit	0.0700 μs	0.0800 μs

CollectionEquatable (dynamic, medium)

stat	Before	After
total runs	251 419	217 705
total time	2.0000 s	2.0000 s
average run	7 μs	9 μs
runs/second	142 857	111 111
units	100	100
units/second	14 285 714	11 111 111
time per unit	0.0700 μs	0.0900 μs

CollectionEquatable (dynamic, large)

stat	Before	After
total runs	249 609	215 003
total time	2.0000 s	2.0000 s
average run	8 μs	9 μs
runs/second	125 000	111 111
units	100	100
units/second	12 500 000	11 111 111
time per unit	0.0800 μs	0.0900 μs

[ShakyaCsun]

1. the setEquals function can be safely deleted now and replaced with iterableEquals in the tests but looking at the comment on equals function i.e. breaking change: equals removed in v2.0.6 #187, I decided to leave it in for now.
2. I used propsEquals instead of modifying and using equals to avoid checking for null, but maybe we can remove nullable params from equals instead?
3. I also noticed we could change mapPropsToHashCode to take List<Object?> instead of Iterable<Object?>? and avoid null checks there as well but wanted to get your thoughts before changing function signatures even though these utils aren't publicly exported.
4. Even though Equatable objects with Iterable and List with same elements are no longer equal, they still produce the same hashCode. One idea I had was to change

   equatable/lib/src/equatable_utils.dart

   Line 102 in 834d167

   return hash ^ object.length;

   to

return hash ^ (object is List ? 'List${object.length}'.hashCode : object.length);

but maybe there's a better way