Fix JSON parser handling for certain objects (#7162)

This PR also adds some comments and simplifies
the code. Primary handling is done to ensure
that we make sure to honor cached buffer.

Added unit tests as well

Fixes #7141

vendor/vendor.json

@@ -115,6 +115,12 @@
 			"revision": "6fe16293d6b7af4f5c2450714c5b4825c8ad040c",
 			"revisionTime": "2017-09-25T03:23:15Z"
 		},
+		{
+			"checksumSHA1": "mSo9Sti7F6+laUs4NLx/p23rHD0=",
+			"path": "github.com/bcicen/jstream",
+			"revision": "f306cd3e1fa602a1b513114521a0d6a5a9d5c919",
+			"revisionTime": "2019-02-06T02:23:53Z"
+		},
 		{
 			"checksumSHA1": "0rido7hYHQtfq3UJzVT5LClLAWc=",
 			"path": "github.com/beorn7/perks/quantile",