Replace Hashtable with Dictionary.

StackExchange.Redis/StackExchange/Redis/LuaScript.cs

 using System;
 using System.Collections;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 
 namespace StackExchange.Redis
@@ -39,7 +40,7 @@ public sealed class LuaScript
 
         bool HasArguments { get { return Arguments != null && Arguments.Length > 0; } }
 
-        Hashtable ParameterMappers;
+        Dictionary<Type, Func<object, RedisKey?, ScriptParameterMapper.ScriptParameters>> ParameterMappers;
 
         internal LuaScript(string originalScript, string executableScript, string[] arguments)
         {
@@ -49,7 +50,7 @@ internal LuaScript(string originalScript, string executableScript, string[] argu
 
             if (HasArguments)
             {
-                ParameterMappers = new Hashtable();
+                ParameterMappers = new Dictionary<Type, Func<object, RedisKey?, ScriptParameterMapper.ScriptParameters>>();
             }
         }
 
@@ -109,12 +110,12 @@ internal void ExtractParameters(object ps, RedisKey? keyPrefix, out RedisKey[] k
                 if (ps == null) throw new ArgumentNullException("ps", "Script requires parameters");
 
                 var psType = ps.GetType();
-                var mapper = (Func<object, RedisKey?, ScriptParameterMapper.ScriptParameters>)ParameterMappers[psType];
+                var mapper = ParameterMappers[psType];
                 if (ps != null && mapper == null)
                 {
                     lock (ParameterMappers)
                     {
-                        mapper = (Func<object, RedisKey?, ScriptParameterMapper.ScriptParameters>)ParameterMappers[psType];
+                        mapper = ParameterMappers[psType];
                         if (mapper == null)
                         {
                             string missingMember;

StackExchange.Redis_NetCore/StackExchange.Redis_NetCore.csproj

@@ -25,6 +25,7 @@
     <DefineConstants>TRACE;DEBUG;NETCORE;</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -33,6 +34,7 @@
     <DefineConstants>TRACE;NETCORE;</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <ItemGroup>
     <None Include="project.json" />

StackExchange.Redis_NetCore/project.json

@@ -5,7 +5,9 @@
   },
   "dependencies": {
     "Microsoft.NETCore": "5.0.0",
-    "Microsoft.NETCore.Portable.Compatibility": "1.0.0"
+    "Microsoft.NETCore.Portable.Compatibility": "1.0.0",
+    "System.Collections": "4.0.10",
+    "System.Reflection.Emit": "4.0.0"
   },
   "frameworks": {
     "dotnet": {