read size affects the overlap of disk
reads/writes with network reads/writes. If the amount of data being
transferred in several of the SMB commands (currently SMBwrite, SMBwriteX, and
SMBreadbraw) is larger than this value, then the server begins writing
the data before it has received the whole packet from the network, or
in the case of SMBreadbraw, it begins writing to the network before
all the data has been read from disk.
This overlapping works best when the speeds of disk and network access
are similar, having little effect when the speed of one is much
greater than the other.
The default value is 16384, but little experimentation has been
done as yet to determine the optimal value, and it is likely that the best
value will vary greatly between systems anyway. A value over 65536 is
pointless and will cause you to allocate memory unnecessarily.