( resource connection, string stmtname, string query )
Sends a request to create a prepared statement with the given parameters,
without waiting for completion.
This is an asynchronous version of pg_prepare(): it returns TRUE if it was able to
dispatch the request, and FALSE if not. After a successful call, call
pg_get_result() to determine whether the server successfully created the
prepared statement. The function's parameters are handled identically to
pg_prepare(). Like pg_prepare(), it will not work
on pre-7.4 versions of PostgreSQL.