Similar to dialMPTCP, this listenMPTCP function is called when the user
has requested MPTCP via SetMultipathTCP in the ListenConfig.
This function falls back to listenTCP on operating systems that do not
support MPTCP or if MPTCP is not supported.
On ListenConfig side, MultipathTCP function can be used to know if the
package will try to use MPTCP or not when Listen is called.
Note that this new listenMPTCP function returns a TCPListener object and
not a new MPTCP dedicated one. The reasons are similar as the ones
explained in the parent commit introducing dialTCP: if MPTCP is used by
default later, Listen will return a different object that could break
existing applications expecting TCPListener.
This work has been co-developped by Gregory Detal
<gregory.detal@tessares.net>.
Updates #56539
Change-Id: I010f1d87f921bbac9e157cef2212c51917852353
Reviewed-on: https://go-review.googlesource.com/c/go/+/471137
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com>