header.go Referer() optimize (#1313)

* args.go GetBool(): use switch with string casting

This should be optimized by Go compiler itself so the b2s() call is not needed.

It was previously done by this but changed in
1e7885eb56cdf4c6f550e143b0dbd3acc82a4137

* header.go Referer() optimize

Use direct peekArgBytes() instead of PeekBytes() that will check for special headers

* header_timing_test.go BenchmarkRequestHeaderPeekBytesSpecialHeader

The old BenchmarkRequestHeaderPeekBytesCanonical and BenchmarkRequestHeaderPeekBytesNonCanonical are in fact just measured the header normalization.
But it's anyway is benchmarked separately.
Results was almost the same: 1.5 ns/op.

Instead, let's reuse the benches to find a difference between peeking of special (Host, CT) and custom headers.

1 files changed, 1 insertions, 1 deletions

diff --git a/header.go b/header.go
index fc61ae2..e7616df 100644
--- a/header.go
+++ b/header.go
@@ -586,7 +586,7 @@ func (h *RequestHeader) SetUserAgentBytes(userAgent []byte) {
 
 // Referer returns Referer header value.
 func (h *RequestHeader) Referer() []byte {
-	return h.PeekBytes(strReferer)
+	return peekArgBytes(h.h, strReferer)
 }
 
 // SetReferer sets Referer header value.