Optimizations (#138)

* Use TryGetValue over ContainsKey+Indexer

* Use generic comparison to avoid boxing

Author: jnyrup

src/GeoJSON.Net/CoordinateReferenceSystem/CRSBase.cs

@@ -74,11 +74,11 @@ public bool Equals(CRSBase left, CRSBase right)
 
             foreach (var item in left.Properties)
             {
-                if (!right.Properties.ContainsKey(item.Key))
+                if (!right.Properties.TryGetValue(item.Key, out object rightValue))
                 {
                     return false;
                 }
-                if (!object.Equals(item.Value, right.Properties[item.Key]))
+                if (!object.Equals(item.Value, rightValue))
                 {
                     return false;
                 }

src/GeoJSON.Net/Feature/Feature.cs

@@ -190,7 +190,7 @@ public bool Equals(Feature<TGeometry> other)
                 return false;
             }
 
-            return Geometry.Equals(other.Geometry);
+            return EqualityComparer<TGeometry>.Default.Equals(Geometry, other.Geometry);
         }
 
         public override bool Equals(object obj)
@@ -215,4 +215,4 @@ public override int GetHashCode()
             return !(left?.Equals(right) ?? ReferenceEquals(null, right));
         }
     }
-}
+}

src/GeoJSON.Net/Geometry/LineString.cs

@@ -68,7 +68,7 @@ public bool IsClosed()
 
             return firstCoordinate.Longitude.Equals(lastCoordinate.Longitude)
                    && firstCoordinate.Latitude.Equals(lastCoordinate.Latitude)
-                   && firstCoordinate.Altitude.Equals(lastCoordinate.Altitude);
+                   && Nullable.Equals(firstCoordinate.Altitude, lastCoordinate.Altitude);
         }
 
         /// <summary>