The
GetData type is used to retrieve information on a specific
object (
Block or
Tx) identified by the objects hash.
The payload of a
GetData request is a list of
InvVector
which represent all the hashes of objects that a node wants. The
response to a
GetBlock message will be either a
Block or a
Tx message depending on the type of the
object referenced by the hash. Usually,
GetData messages are
sent after a node receives an
Inv message that contains unknown
object hashes.