Performance issue in PR (#1391)

[appleboy]

#1391 trigger the performance issue.

benchmark:

pkg: github.com/julienschmidt/go-http-routing-benchmark
BenchmarkEcho_Param        	13535522	        88.0 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param         	 5361892	       238 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_Param5       	 5008866	       244 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param5        	 4290758	       272 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_Param20      	 1641387	       760 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param20       	 2317610	       521 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_ParamWrite   	 5904582	       203 ns/op	       8 B/op	       1 allocs/op
BenchmarkGin_ParamWrite    	 4513596	       267 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GithubStatic 	 9554672	       144 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubStatic  	 4920577	       246 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GithubParam  	 4610731	       246 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubParam   	 4571893	       338 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GithubAll    	   22447	     55123 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubAll     	   18040	     65561 ns/op	    6496 B/op	     203 allocs/op
BenchmarkEcho_GPlusStatic  	12387967	        87.6 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusStatic   	 5539902	       230 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GPlusParam   	 8484045	       136 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusParam    	 4628140	       257 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GPlus2Params 	 5794423	       209 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlus2Params  	 4435572	       260 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_GPlusAll     	  567093	      2104 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusAll      	  327002	      3349 ns/op	     416 B/op	      13 allocs/op
BenchmarkEcho_ParseStatic  	13683361	        88.8 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseStatic   	 5690004	       218 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_ParseParam   	11511034	       109 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseParam    	 5031255	       247 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_Parse2Params 	 7868221	       152 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Parse2Params  	 4861460	       261 ns/op	      32 B/op	       1 allocs/op
BenchmarkEcho_ParseAll     	  318800	      3533 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseAll      	  230422	      6377 ns/op	     832 B/op	      26 allocs/op
BenchmarkEcho_StaticAll    	   40495	     29597 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_StaticAll     	   29606	     42596 ns/op	    5024 B/op	     157 allocs/op

Without #1391 commit:

pkg: github.com/julienschmidt/go-http-routing-benchmark
BenchmarkEcho_Param        	13765762	        88.7 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param         	16475670	        78.0 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_Param5       	 5095788	       239 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param5        	 8914904	       135 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_Param20      	 1580520	       759 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Param20       	 3694677	       321 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_ParamWrite   	 6190405	       204 ns/op	       8 B/op	       1 allocs/op
BenchmarkGin_ParamWrite    	 7506909	       151 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GithubStatic 	 9014336	       130 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubStatic  	10326368	       123 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GithubParam  	 4447852	       279 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubParam   	 6891337	       174 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GithubAll    	   25905	     46867 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GithubAll     	   36128	     32502 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GPlusStatic  	13771851	        88.7 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusStatic   	16447762	        78.9 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GPlusParam   	 8797988	       133 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusParam    	11276586	       106 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GPlus2Params 	 5849034	       201 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlus2Params  	 9059781	       131 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_GPlusAll     	  596871	      1998 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_GPlusAll      	  732151	      1584 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_ParseStatic  	12376551	       128 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseStatic   	10699678	       106 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_ParseParam   	 9799104	       127 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseParam    	13203855	       127 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_Parse2Params 	 6864175	       184 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_Parse2Params  	10904766	       122 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_ParseAll     	  260600	      4147 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_ParseAll      	  378186	      2756 ns/op	       0 B/op	       0 allocs/op
BenchmarkEcho_StaticAll    	   30274	     34241 ns/op	       0 B/op	       0 allocs/op
BenchmarkGin_StaticAll     	   37824	     28181 ns/op	       0 B/op	       0 allocs/op

How to test

git clone https://github.com/appleboy/go-http-routing-benchmark.git
# performance issue
go test -bench="Gin|Echo"
# without performance
go get github.com/gin-gonic/gin@67008be35f5432aeec06641540f3b6df3eac8747
go test -bench="Gin|Echo"