Description:

bfr is a general-purpose command-line pipe buffer. It buffers data from stdin
and sends it to stdout, adjusting to best fit the pace stdout can handle.
It can solve problems on either end of a pipe. For instance, if the incoming
stream is slower than outgoing, performance is mainly dependent on the
"start-stream threshold" you set.
This can be used to group data into larger packets to, for an example, reduce
seeking on a tape drive. In the case of the outgoing being slower, the
"stop-stream threshold" prevents unnecessary CPU from being taken up by
reading single-bytes and such (if the output stream accepts data one byte at a
time, for instance), and will output-only until the buffer goes down to 97% or
so. This speeds up certain procedures, such as creating a tar file, gzipping
it, and putting it through a program such as "netcat".
It boosts performance by allowing a certain level of detachment between the
two... allowing tar and (especially) gzip to do its work at the same time the
network is doing its work, so you're not sending one packet and THEN seeing
gzip kick in to create the next.