public boolean isPoolingEnabled() {
        return poolingEnabled;
    }
Returns whether or not connection pooling should be used when possible and appropriate.  This property is NOT
backed by the {@link #getEnvironment() environment template} like most other properties in this class.  It
is a flag to indicate that pooling is preferred.  The default value is {@code true}.
<p/>
However, pooling will only actually be enabled if this property is {@code true} <em>and</em> the connection
being created is for the {@link #getSystemUsername() systemUsername} user.  Connection pooling is not used for
general authentication attempts by application end-users because the probability of re-use for that same
user-specific connection after an authentication attempt is extremely low.
<p/>
If this attribute is {@code true} and it has been determined that the connection is being made with the
{@link #getSystemUsername() systemUsername}, the
{@link #getLdapContext(Object, Object)} implementation will set the Sun/Oracle-specific
{@code com.sun.jndi.ldap.connect.pool} environment property to &quot;{@code true}&quot;.  This means setting
this property is only likely to work if using the Sun/Oracle default context factory class (i.e. not using
a custom {@link #getContextFactoryClassName() contextFactoryClassName}).

@return whether or not connection pooling should be used when possible and appropriate
core/src/main/java/org/apache/shiro/realm/ldap/JndiLdapContextFactory.java