Increased connection pool timeout to 60 seconds

app/src/main/java/eu/faircode/email/EmailService.java

@@ -130,7 +130,8 @@ public class EmailService implements AutoCloseable {
 
     private final static int SEARCH_TIMEOUT = 90 * 1000; // milliseconds
     private final static int FETCH_SIZE = 1024 * 1024; // bytes, default 16K
-    private final static int POOL_TIMEOUT = 45 * 1000; // milliseconds, default 45 sec
+    private final static int POOL_SIZE = 2; // connections
+    private final static int POOL_TIMEOUT = 60 * 1000; // milliseconds, default 45 sec
 
     private final static int TCP_KEEP_ALIVE_INTERVAL = 9 * 60; // seconds
 
@@ -232,7 +233,7 @@ public class EmailService implements AutoCloseable {
 
             properties.put("mail." + protocol + ".separatestoreconnection", "true");
             properties.put("mail." + protocol + ".connectionpool.debug", "true");
-            properties.put("mail." + protocol + ".connectionpoolsize", Integer.toString(2));
+            properties.put("mail." + protocol + ".connectionpoolsize", Integer.toString(POOL_SIZE));
             properties.put("mail." + protocol + ".connectionpooltimeout", Integer.toString(POOL_TIMEOUT));
 
             properties.put("mail." + protocol + ".finalizecleanclose", "false");