ansible: double the default pool size.

Tempted to push this up to 64, but let's do it incrementally just in
case.

ansible_mitogen/process.py

@@ -274,7 +274,7 @@ class MuxProcess(object):
                 ansible_mitogen.services.ContextService(self.router),
                 ansible_mitogen.services.ModuleDepService(self.router),
             ],
-            size=getenv_int('MITOGEN_POOL_SIZE', default=16),
+            size=getenv_int('MITOGEN_POOL_SIZE', default=32),
         )
         LOG.debug('Service pool configured: size=%d', self.pool.size)
 

docs/ansible.rst

@@ -179,7 +179,7 @@ Noteworthy Differences
   practice, and light web searches failed to reveal many examples of them.
 
 * Ansible permits up to ``forks`` connections to be setup in parallel, whereas
-  in Mitogen this is handled by a fixed-size thread pool. Up to 16 connections
+  in Mitogen this is handled by a fixed-size thread pool. Up to 32 connections
   may be established in parallel by default, this can be modified by setting
   the ``MITOGEN_POOL_SIZE`` environment variable.