A decoded ut_metadata message.
ut_metadata
for a Type.DATA message, the raw piece bytes that followed the bencode dict; an empty array otherwise.
the 0-based 16 KiB piece index.
for a Type.DATA message, the total metadata length the sender advertises; 0 / meaningless for request and reject. libtorrent reads it with dict_find_int_value("total_size", 0).
0
dict_find_int_value("total_size", 0)
the Type (request / data / reject).