new concurrency model :shared

Fixes #96

Author: ph

lib/logstash/outputs/s3.rb

@@ -79,6 +79,8 @@ class LogStash::Outputs::S3 < LogStash::Outputs::Base
   config_name "s3"
   default :codec, 'line'
 
+  concurrency :shared
+
   # S3 bucket
   config :bucket, :validate => :string
 
@@ -214,8 +216,6 @@ def register
     # http://ruby.awsblog.com/post/Tx16QY1CI5GVBFT/Threading-with-the-AWS-SDK-for-Ruby
     AWS.eager_autoload!(AWS::S3)
 
-    workers_not_supported
-
     @s3 = aws_s3_config
     @upload_queue = Queue.new
     @file_rotation_lock = Mutex.new