Refactor event handling and improve argument validation across indicators

- Updated event handler signatures to use TValueEventArgs for consistency in Mama, Mgdi, Pwma, Rma, Sma, Ssf, Super, T3, Tema, Trima, Usf, Vidya, Wma, and Atr classes.
- Enhanced argument validation by specifying parameter names in exceptions for clarity.
- Adjusted tests to align with new event handler signatures.
- Improved code readability and maintainability by using structured records and lambda expressions.

lib/statistics/covariance/Covariance.cs

@@ -180,7 +180,7 @@ public sealed class Covariance : AbstractBase
     public static TSeries Calculate(TSeries sourceX, TSeries sourceY, int period, bool isPopulation = false)
     {
         if (sourceX.Count != sourceY.Count)
-            throw new ArgumentException("Source series must have the same length");
+            throw new ArgumentException("Source series must have the same length", nameof(sourceY));
 
         int len = sourceX.Count;
         var t = new List<long>(len);
@@ -201,7 +201,7 @@ public sealed class Covariance : AbstractBase
     public static void Batch(ReadOnlySpan<double> sourceX, ReadOnlySpan<double> sourceY, Span<double> output, int period, bool isPopulation = false)
     {
         if (sourceX.Length != sourceY.Length || sourceX.Length != output.Length)
-            throw new ArgumentException("All spans must have the same length");
+            throw new ArgumentException("All spans must have the same length", nameof(output));
         if (period < 2)
             throw new ArgumentException("Period must be greater than or equal to 2", nameof(period));
 

lib/statistics/linreg/LinReg.cs

@@ -36,9 +36,11 @@ public sealed class LinReg : AbstractBase
     private readonly double _sum_x;
     private readonly double _denominator;
 
+    [StructLayout(LayoutKind.Auto)]
     private record struct State(double SumY, double SumXY, double SumY2, double LastVal, double LastValidValue);
     private State _state;
     private State _p_state;
+    private readonly TValuePublishedHandler _handler;
 
     private int _tickCount;
     private const int ResyncInterval = 1000;
@@ -81,6 +83,7 @@ public sealed class LinReg : AbstractBase
         _buffer = new RingBuffer(period);
         Name = $"LinReg({period})";
         WarmupPeriod = period;
+        _handler = Handle;
 
         // Precalculate constants
         // sum_x = 0 + 1 + ... + (n-1) = n(n-1)/2
@@ -95,9 +98,12 @@ public sealed class LinReg : AbstractBase
 
     public LinReg(ITValuePublisher source, int period, int offset = 0) : this(period, offset)
     {
-        source.Pub += (item) => Update(item);
+        source.Pub += _handler;
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private void Handle(object? sender, TValueEventArgs args) => Update(args.Value, args.IsNew);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private double GetValidValue(double input)
     {
@@ -250,7 +256,7 @@ public sealed class LinReg : AbstractBase
         }
 
         Last = new TValue(input.Time, result);
-        PubEvent(Last);
+        PubEvent(Last, isNew);
         return Last;
     }
 
@@ -329,7 +335,7 @@ public sealed class LinReg : AbstractBase
     public static void Calculate(ReadOnlySpan<double> source, Span<double> output, int period, int offset = 0, double initialLastValid = 0)
     {
         if (source.Length != output.Length)
-            throw new ArgumentException("Source and output must have the same length");
+            throw new ArgumentException("Source and output must have the same length", nameof(output));
         if (period <= 0)
             throw new ArgumentException("Period must be greater than 0", nameof(period));
 

lib/statistics/median/Median.Validation.Tests.cs

@@ -88,7 +88,7 @@ public sealed class MedianValidationTests : IDisposable
         }
     }
 
-    private static double CalculateMedian(List<double> sortedWindow)
+    private static double CalculateMedian(IReadOnlyList<double> sortedWindow)
     {
         int count = sortedWindow.Count;
         if (count == 0) return 0; // Or NaN

lib/statistics/median/Median.cs

@@ -25,6 +25,7 @@ public sealed class Median : AbstractBase
     private readonly int _period;
     private readonly RingBuffer _buffer;
     private readonly double[] _sortedBuffer;
+    private readonly TValuePublishedHandler _handler;
 
     /// <summary>
     /// Creates a Median indicator with the specified period.
@@ -40,11 +41,12 @@ public sealed class Median : AbstractBase
         _sortedBuffer = new double[period];
         Name = $"Median({period})";
         WarmupPeriod = period;
+        _handler = Handle;
     }
 
     public Median(ITValuePublisher source, int period) : this(period)
     {
-        source.Pub += (item) => Update(item);
+        source.Pub += _handler;
     }
 
     public Median(TSeries source, int period) : this(period)
@@ -54,7 +56,7 @@ public sealed class Median : AbstractBase
         {
             Last = new TValue(source.LastTime, Last.Value);
         }
-        source.Pub += (item) => Update(item);
+        source.Pub += _handler;
     }
 
     /// <summary>
@@ -79,6 +81,9 @@ public sealed class Median : AbstractBase
         }
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private void Handle(object? sender, TValueEventArgs args) => Update(args.Value, args.IsNew);
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public override TValue Update(TValue input, bool isNew = true)
     {
@@ -123,7 +128,7 @@ public sealed class Median : AbstractBase
         }
 
         Last = new TValue(input.Time, median);
-        PubEvent(Last);
+        PubEvent(Last, isNew);
         return Last;
     }
 
@@ -202,7 +207,7 @@ public sealed class Median : AbstractBase
     public static void Batch(ReadOnlySpan<double> source, Span<double> output, int period)
     {
         if (source.Length != output.Length)
-            throw new ArgumentException("Source and output must have the same length");
+            throw new ArgumentException("Source and output must have the same length", nameof(output));
         if (period <= 0)
             throw new ArgumentException("Period must be greater than 0", nameof(period));
 

lib/statistics/skew/Skew.cs

@@ -205,7 +205,7 @@ public sealed class Skew : AbstractBase
     public static void Batch(ReadOnlySpan<double> source, Span<double> output, int period, bool isPopulation = false)
     {
         if (source.Length != output.Length)
-            throw new ArgumentException("Source and output must have the same length");
+            throw new ArgumentException("Source and output must have the same length", nameof(output));
         if (period < 3)
             throw new ArgumentException("Period must be greater than or equal to 3", nameof(period));
 

lib/statistics/variance/Variance.cs

@@ -181,7 +181,7 @@ public sealed class Variance : AbstractBase
     public static void Batch(ReadOnlySpan<double> source, Span<double> output, int period, bool isPopulation = false)
     {
         if (source.Length != output.Length)
-            throw new ArgumentException("Source and output must have the same length");
+            throw new ArgumentException("Source and output must have the same length", nameof(output));
         if (period < 2)
             throw new ArgumentException("Period must be greater than or equal to 2", nameof(period));