cancel context.CancelCauseFunc

	mu  sync.Mutex // guards err
	err error      // first setError value for mapRoundTripError to consider
}

func (tr *transportRequest) extraHeaders() Header {
	if tr.extra == nil {
		tr.extra = make(Header)
	}
	return tr.extra
}

func (tr *transportRequest) setError(err error) {
	tr.mu.Lock()
	if tr.err == nil {
		tr.err = err
	}
	tr.mu.Unlock()
}

				child.AddASN1(cryptobyte_asn1.SEQUENCE, func(child *cryptobyte.Builder) {
					child.AddASN1(cryptobyte_asn1.OBJECT_IDENTIFIER, func(child *cryptobyte.Builder) {
						if len(v.der) == 0 {
							child.SetError(errors.New("invalid policy object identifier"))
							return
						}
						child.AddBytes(v.der)
					})
				})
			}
		} else {
			for _, v := range policyIdentifiers {

		}
		fmt.Fprint(fgo2, "\t")
		if !void {
			fmt.Fprint(fgo2, "r := ")
		}
		fmt.Fprintf(fgo2, "%s(%s)\n", cname, strings.Join(paramnames, ", "))

		if n.AddError {
			fmt.Fprint(fgo2, "\te := syscall.GetErrno()\n")
			fmt.Fprint(fgo2, "\tif e != 0 {\n")
			fmt.Fprint(fgo2, "\t\treturn ")
			if !void {
				fmt.Fprint(fgo2, "r, ")
			}
			fmt.Fprint(fgo2, "e\n")
			fmt.Fprint(fgo2, "\t}\n")