On 16th of February, , Robert Haas committed patch:
Fujii Masao, reviewed by Robert Haas, Stephen Frost, and Magnus Hagander.
Commit log is very short, functionality is not really new, but the important thing is that we're getting support for PostgreSQL replication in more “administrative" places, which makes the whole process more streamlined.
Basically this commit adds another way of finishing streaming. Instead of using trigger file, you can now simply do
pg_ctl -D /DATA promote
to change your SR-Slave into standalone Pg.