/b_read                Read sound file data into an existing buffer

int    - buffer number
string - path name of a sound file
int    - starting frame in file (optional, default = 0)
int    - number of frames to read (optional, default = -1, see below)
int    - starting frame in buffer (optional, default = 0)
int    - leave file open (optional, default = 0)
bytes  - an OSC message to execute upon completion (optional)

Reads sound file data from the given starting frame in the file and
writes it to the given starting frame in the buffer. If number of
frames is less than zero, the entire file is read.  If reading a file
to be used by DiskIn ugen then you will want to set "leave file open"
to one, otherwise set it to zero.

Asynchronous.  Replies to sender with /done when complete.