Make content-legnth as method

[mattn]

This will make faster.

Before:

Concurrency Level:      10
Time taken for tests:   17.712542 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Keep-Alive requests:    0
Total transferred:      119000 bytes
HTML transferred:       9000 bytes
Requests per second:    56.46 [#/sec] (mean)
Time per request:       177.125 [ms] (mean)
Time per request:       17.713 [ms] (mean, across all concurrent requests)
Transfer rate:          6.55 [Kbytes/sec] received

After:

Concurrency Level:      10
Time taken for tests:   16.309762 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Keep-Alive requests:    0
Total transferred:      119000 bytes
HTML transferred:       9000 bytes
Requests per second:    61.31 [#/sec] (mean)
Time per request:       163.098 [ms] (mean)
Time per request:       16.310 [ms] (mean, across all concurrent requests)
Transfer rate:          7.11 [Kbytes/sec] received

[tokuhirom]

LGTM