Updated to use broader list.

Author: Oren (electricessence)

Open.Numeric.csproj

@@ -18,8 +18,8 @@
 		<PackageProjectUrl>https://github.com/electricessence/Open.Numeric/</PackageProjectUrl>
 		<RepositoryType>git</RepositoryType>
 		<PackageTags>dotnet, dotnetcore, cs, numbers, double, float, precision, extensions</PackageTags>
-		<Version>2.1.2</Version>
-		<PackageReleaseNotes>Added .NET Standard 2.1 support.</PackageReleaseNotes>
+		<Version>2.2.0</Version>
+		<PackageReleaseNotes></PackageReleaseNotes>
 		<PackageLicenseExpression>MIT</PackageLicenseExpression>
 		<Nullable>enable</Nullable>
 	</PropertyGroup>

ProcedureResults.cs

@@ -48,7 +48,7 @@ static ImmutableArray<T> ToImmutableArray<T>(in ReadOnlySpan<T> source)
 			return builder.MoveToImmutable();
 		}
 
-		static ImmutableArray<double> SumValues(IList<double> a, IList<double> b)
+		static ImmutableArray<double> SumValues(IReadOnlyList<double> a, IReadOnlyList<double> b)
 		{
 			var len = a.Count;
 			if (len != b.Count)
@@ -61,7 +61,7 @@ static ImmutableArray<double> SumValues(IList<double> a, IList<double> b)
 			return result.MoveToImmutable();
 		}
 
-		static ImmutableArray<double> SumValues(IList<double> a, in ReadOnlySpan<double> b)
+		static ImmutableArray<double> SumValues(IReadOnlyList<double> a, in ReadOnlySpan<double> b)
 		{
 			var len = a.Count;
 			if (len != b.Length)
@@ -74,7 +74,7 @@ static ImmutableArray<double> SumValues(IList<double> a, in ReadOnlySpan<double>
 			return result.MoveToImmutable();
 		}
 
-		public ProcedureResults Add(IList<double> values, int count = 1)
+		public ProcedureResults Add(IReadOnlyList<double> values, int count = 1)
 			=> new ProcedureResults(SumValues(Sum, values), Count + count);
 
 		public ProcedureResults Add(in ReadOnlySpan<double> values, int count = 1)