create a bare httptrace.ClientTrace implementation

httptrace.awk

#!/usr/bin/env -S awk -f
# usage: go doc httptrace.ClientTrace | trace.awk
BEGIN {
  flag=0;
}

# check if we are inside the struct.
/{/ { flag=1 }
/}/ { flag=0 }

# print comments as is.
/\/\// && flag { print $0 }

# manipulate func defs
/func/ && flag { 
  sub(/ func/, "", $0);
  sub(/DNSStartInfo/, "si httptrace.DNSStartInfo", $0);
  sub(/DNSDoneInfo/, "di httptrace.DNSDoneInfo", $0);
  sub(/WroteRequestInfo/, "ri httptrace.WroteRequestInfo", $0);
  sub(/GotConnInfo/, "ri httptrace.GotConnInfo", $0);
  sub(/, error/, ", err error", $0);
  print "func (t *httpTrace)", $0, "{}";
}