Description
The function is used for polling for events, such as user input and window resize events. Upon calling
this function, all window states, keyboard states and mouse states are updated. If any related callback
functions are registered, these are called during the call to glfwPollEvents.

Notes
glfwPollEvents is called implicitly from glfwSwapBuffers if GLFW_AUTO_POLL_EVENTS is
enabled (default). Thus, if glfwSwapBuffers is called frequently, which is normally the case, there is
no need to call glfwPollEvents.