Fixes System.Data.SQLite Close() not releasing database file , see https://stackoverflow.com/a/38268171

ClearSQLiteCommandConnectionHelper.cs

using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
using System.Linq;

public static class ClearSQLiteCommandConnectionHelper
{
    private static readonly object lockObject = new object();
    private static readonly List<SQLiteCommand> OpenCommands = new List<SQLiteCommand>();

    public static void Initialise()
    {
        SQLiteConnection.Changed += SqLiteConnectionOnChanged;
    }

    private static void SqLiteConnectionOnChanged(object sender, ConnectionEventArgs connectionEventArgs)
    {
        if (connectionEventArgs.EventType == SQLiteConnectionEventType.NewCommand && connectionEventArgs.Command is SQLiteCommand)
        {
            lock(lockObject)
            {
                OpenCommands.Add((SQLiteCommand) connectionEventArgs.Command);
            }
        }
        else if (connectionEventArgs.EventType == SQLiteConnectionEventType.DisposingCommand && connectionEventArgs.Command is SQLiteCommand)
        {
            lock(lockObject)
            {
                OpenCommands.Remove((SQLiteCommand) connectionEventArgs.Command);
            }
        }

        if (connectionEventArgs.EventType == SQLiteConnectionEventType.Closed)
        {
            lock(lockObject)
            {
                var commands = OpenCommands.ToList();
                foreach (var cmd in commands)
                {
                    if (cmd.Connection == null)
                    {
                        OpenCommands.Remove(cmd);
                    }
                    else if (cmd.Connection.State == ConnectionState.Closed)
                    {
                        cmd.Connection = null;
                        OpenCommands.Remove(cmd);
                    }
                }
            }
        }
    }
}