feature: README add connection pool config

README.md

@@ -26,7 +26,7 @@ mvn install:install-file -DgroupId=org.csource -DartifactId=fastdfs-client-java
 <dependency>
     <groupId>org.csource</groupId>
     <artifactId>fastdfs-client-java</artifactId>
-    <version>1.27-SNAPSHOT</version>
+    <version>1.28-SNAPSHOT</version>
 </dependency>
 ```
 
@@ -53,6 +53,11 @@ http.secret_key = FastDFS1234567890
 tracker_server = 10.0.11.247:22122
 tracker_server = 10.0.11.248:22122
 tracker_server = 10.0.11.249:22122
+
+connection_pool.enabled = true
+connection_pool.max_count_per_entry = 500
+connection_pool.max_idle_time = 3600
+connection_pool.max_wait_time_in_ms = 1000
 ```
 
     注1：tracker_server指向您自己IP地址和端口，1-n个
@@ -80,6 +85,11 @@ fastdfs.http_secret_key = FastDFS1234567890
 fastdfs.http_tracker_http_port = 80
 
 fastdfs.tracker_servers = 10.0.11.201:22122,10.0.11.202:22122,10.0.11.203:22122
+
+fastdfs.connection_pool.enabled = true
+fastdfs.connection_pool.max_count_per_entry = 500
+fastdfs.connection_pool.max_idle_time = 3600
+fastdfs.connection_pool.max_wait_time_in_ms = 1000
 ```
 
     注1：properties 配置文件中属性名跟 conf 配置文件不尽相同，并且统一加前缀"fastdfs."，便于整合到用户项目配置文件
@@ -122,6 +132,10 @@ ClientGlobal.configInfo(): {
   g_anti_steal_token = false
   g_secret_key = FastDFS1234567890
   g_tracker_http_port = 80
+  g_connection_pool_enabled = true
+  g_connection_pool_max_count_per_entry = 500
+  g_connection_pool_max_idle_time(ms) = 3600000
+  g_connection_pool_max_wait_time_in_ms(ms) = 1000
   trackerServers = 10.0.11.101:22122,10.0.11.102:22122
 }
 ```