Fixed immutable usage.

Author: Oren (electricessence)

Open.Numeric.csproj

@@ -18,7 +18,7 @@
 		<PackageProjectUrl>https://github.com/electricessence/Open.Numeric/</PackageProjectUrl>
 		<RepositoryType>git</RepositoryType>
 		<PackageTags>dotnet, dotnetcore, cs, numbers, double, float, precision, extensions</PackageTags>
-		<Version>2.2.1</Version>
+		<Version>2.2.2</Version>
 		<PackageReleaseNotes></PackageReleaseNotes>
 		<PackageLicenseExpression>MIT</PackageLicenseExpression>
 		<Nullable>enable</Nullable>

ProcedureResults.cs

@@ -44,8 +44,8 @@ static ImmutableArray<T> ToImmutableArray<T>(in ReadOnlySpan<T> source)
 			var len = source.Length;
 			var builder = ImmutableArray.CreateBuilder<T>(len);
 			for (var i = 0; i < len; i++)
-				builder[i] = source[i];
-			return builder.ToImmutable();
+				builder.Add(source[i]);
+			return builder.MoveToImmutable();
 		}
 
 		static ImmutableArray<double> SumValues(IReadOnlyList<double> a, IReadOnlyList<double> b)
@@ -54,11 +54,11 @@ static ImmutableArray<double> SumValues(IReadOnlyList<double> a, IReadOnlyList<d
 			if (len != b.Count)
 				throw new ArgumentException("Length mismatch.");
 
-			var result = ImmutableArray.CreateBuilder<double>(len);
+			var builder = ImmutableArray.CreateBuilder<double>(len);
 			for (var i = 0; i < len; i++)
-				result[i] = a[i] + b[i];
+				builder.Add(a[i] + b[i]);
 
-			return result.ToImmutable();
+			return builder.MoveToImmutable();
 		}
 
 		static ImmutableArray<double> SumValues(IReadOnlyList<double> a, in ReadOnlySpan<double> b)
@@ -67,11 +67,11 @@ static ImmutableArray<double> SumValues(IReadOnlyList<double> a, in ReadOnlySpan
 			if (len != b.Length)
 				throw new ArgumentException("Length mismatch.");
 
-			var result = ImmutableArray.CreateBuilder<double>(len);
+			var builder = ImmutableArray.CreateBuilder<double>(len);
 			for (var i = 0; i < len; i++)
-				result[i] = a[i] + b[i];
+				builder.Add(a[i] + b[i]);
 
-			return result.ToImmutable();
+			return builder.MoveToImmutable();
 		}
 
 		public ProcedureResults Add(IReadOnlyList<double> values, int count = 1)