Buffered Send
•We have already discussed the concept of a buffered send .
•The corresponding routine is
•   MPI_BSEND (buf, count, type, dest, tag, comm, ierr)
•This is a blocking send which permits the programmer to allocate required amount of buffer space into which the data can be copied until it is delivered.
•Routine returns after data has been copied from
•    application buffer to the allocated buffer.
•This must be used in conjunction with MPI_BUFFER_ATTACH and MPI_BUFFER_DETACH routines.