How to atomically replace table data in PostgreSQL

I want to replace the entire contents of a table, without affecting any incoming SELECT statements during the process.

The use case is to have a table which stores mailbox information that is regularly extracted, and needs to be stored in a PostgreSQL table. There are many clients using an application that is constantly querying that same table.

Normally, I would do something like (pseudocode incoming)…

BEGIN TRANSACTION
TRUNCATE TABLE
INSERT INTO
COMMIT

But unfortunately the table cannot be read during this process; due to the time it takes INSERT INTO to complete. The table is locked.

In MySQL, I would have used their atomic RENAME TABLE command to avoid these issues…

CREATE TABLE table_new LIKE table; 
INSERT INTO table_new;
RENAME TABLE table TO table_old, table_new TO table; *atomic operation*
DROP TABLE table_old;

How could I achieve this in PostgreSQL?

For the purposes of this question, you can assume I am not using foreign keys.