net: document consecutive dialing in net.Dial
net: document consecutive dialing in net.Dial

document about the consecutive dialing introduced in Go 1.5.
If address is resolved to multiple addresses,
Dial will try each address in order until one succeeds.
Deadline is used to try each address (calculated based on
total number of resolved addresses)

Fixes: #17617

Change-Id: I56b6399edb640c8ef507675f98e0bd45a50d4e2d
Reviewed-on: https://go-review.googlesource.com/34176
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

akutz/go,akutz/go,Cofyc/go,akutz/go,akutz/go,linux-on-ibm-z/go,suncycheng/go,golang/go,golang/go,Cofyc/go,josharian/go,Cofyc/go,codestation/go,cloudflare/go,Cofyc/go,polyverse-security/go,josharian/go,cloudflare/go,vsekhar/elastic-go,vsekhar/elastic-go,derekmarcotte/go,codestation/go,Cofyc/go,suncycheng/go,Cofyc/go,ImJasonH/go,CAFxX/go,ImJasonH/go,cloudflare/go,ImJasonH/go,josharian/go,derekmarcotte/go,cloudflare/go,akutz/go,polyverse-security/go,suncycheng/go,derekmarcotte/go,josharian/go,josharian/go,ImJasonH/go,nawawi/go,suncycheng/go,vsekhar/elastic-go,polyverse-security/go,josharian/go,polyverse-security/go,CAFxX/go,codestation/go,polyverse-security/go,CAFxX/go,polyverse-security/go,codestation/go,golang/go,derekmarcotte/go,codestation/go,nawawi/go,cloudflare/go,cloudflare/go,josharian/go,Cofyc/go,vsekhar/elastic-go,vsekhar/elastic-go,nawawi/go,suncycheng/go,Cofyc/go,derekmarcotte/go,christopher-henderson/Go,golang/go,vsekhar/elastic-go,nawawi/go,linux-on-ibm-z/go,vsekhar/elastic-go,akutz/go,CAFxX/go,linux-on-ibm-z/go,ImJasonH/go,codestation/go,linux-on-ibm-z/go,nawawi/go,polyverse-security/go,nawawi/go,codestation/go,linux-on-ibm-z/go,vsekhar/elastic-go,CAFxX/go,ImJasonH/go,nawawi/go,golang/go,suncycheng/go,akutz/go,golang/go,ImJasonH/go,josharian/go,akutz/go,linux-on-ibm-z/go,nawawi/go,CAFxX/go,golang/go,suncycheng/go,derekmarcotte/go,polyverse-security/go,golang/go,derekmarcotte/go,codestation/go,suncycheng/go,ImJasonH/go,linux-on-ibm-z/go,linux-on-ibm-z/go,cloudflare/go,CAFxX/go,derekmarcotte/go,CAFxX/go,cloudflare/go