void mongoc_write_concern_set_wmajority (mongoc_write_concern_t *write_concern, int32_t wtimeout_msec);
Sets if the write must have been propagated to a majority of nodes before indicating write success.
The timeout specifies how long, in milliseconds, the server should wait before indicating that the write has failed. This is not the same as a socket timeout. A value of zero may be used to indicate no timeout.