evbuffer_ptr_how 2451 opal/mca/event/libevent2022/libevent/buffer.c     size_t position, enum evbuffer_ptr_how how)
evbuffer_ptr_how  601 opal/mca/event/libevent2022/libevent/include/event2/buffer.h     size_t position, enum evbuffer_ptr_how how);