bufio: add (*Reader).WriteTo, (*Writer).ReadFrom to optimize io.Copy

[dvyukov]

For some programs io.Copy() to bufio.Writer causes generation of a lot of garbage.
It seems that bufio.Writer could efficiently support io.ReaderFrom interface to reduce
garbage generation.

[remyoudompheng]

Comment 1:

Similarly I have missed a WriteTo method on bytes.Reader

[rsc]

Comment 2:

I will create a separate issue for package bytes.

Labels changed: added priority-later, go1.1, removed priority-triage.

Status changed to Accepted.

[gopherbot]

Comment 3 by jgraettinger@google.com:

I'd be happy to work up a patch for review.

[nigeltao]

Comment 4:

This issue was updated by revision e289a2b.

R=dave, nigeltao, rsc, bradfitz, rogpeppe
CC=golang-dev
http://golang.org/cl/6548047
Committer: Nigel Tao 

[nigeltao]

Comment 5:

This issue was closed by revision 2a4818d.

Status changed to Fixed.