Dapper.Contrib cannot handle GUID primary keys & SqlMapperExtensions.Insert<T> has wrong usage int & long

SqlMapperExtensions.Insert will fail when numeric db keys reach the Int32 limit (yes, this happens on high traffic dbs) and also fails completely since it assumes primary keys are integers. If primary keys are not integers (i.e. GUIDs or something else) the library fails completely.
Is there any interest for an improvement? I have some proposition in mind.

`        /// <summary>
        /// Inserts an entity into table "Ts" and returns identity id or number of inserted rows if inserting a list.
        /// </summary>
        /// <typeparam name="T">The type to insert.</typeparam>
        /// <param name="connection">Open SqlConnection</param>
        /// <param name="entityToInsert">Entity to insert, can be list of entities</param>
        /// <param name="transaction">The transaction to run under, null (the default) if none</param>
        /// <param name="commandTimeout">Number of seconds before command execution timeout</param>
        /// **<returns>Identity of inserted entity, or number of inserted rows if inserting a list</returns>**
        public static **long** Insert<T>(this IDbConnection connection, T entityToInsert, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
`

Start by inspecting the SqlMapperExtensions.Insert entry point and its XML return documentation. Reproduce inserts with a numeric key near the Int32 limit and with a GUID primary key, then define regression coverage showing that both cases return the documented result without failure.