Original commits:

cacac425  TCP: short writes handling
5d4fa08f  review, skip empty vectors on partial writev
fd4cfa09  tests: TCP short write test with background receiver
aae00f91  fix missing types in declaration
e2604331  tests: larger buffer for TCP short write test
b9f1bf06  remote: use correct timeout values for sent replies
46371cf3  update use of tcp_send_msg()
05e90e75  TCP: no fixed timeout for tcp_send_msg
1bc348ab  TCP: short-write code cleanups
1921eecd  TCP: implement short-write support with fixed timeout
2602dd23  tests: fix setting of nonblocking flag
a1b83687  tests: unit for TCP partial-write
3f37f999  server, define minimal send/receive buffer sizes
bf128651  TCP: increase send buffer size to fit maximum-sized message