remove boost::function from Key.h

gtsam/inference/Key.h

@@ -25,7 +25,6 @@
 #include <gtsam/base/types.h>
 #include <gtsam/dllexport.h>
 
-#include <boost/function.hpp>
 #include <functional>
 
 #include <iosfwd>

gtsam/inference/LabeledSymbol.h

@@ -20,6 +20,7 @@
 #pragma once
 
 #include <gtsam/inference/Symbol.h>
+#include <boost/function.hpp>
 
 namespace gtsam {
 

gtsam/inference/Symbol.h

@@ -21,6 +21,7 @@
 #include <gtsam/inference/Key.h>
 #include <gtsam/base/Testable.h>
 #include <boost/serialization/nvp.hpp>
+#include <boost/function.hpp>
 #include <cstdint>
 
 namespace gtsam {