Get the status of a transaction by ID, provided as a view+seqno pair.
Note that this value is the node's local understanding of the status of that transaction in the network at call time. For a given TxID, the initial status is always UNKNOWN, and eventually becomes COMMITTED or INVALID. See the documentation section titled "Verifying Transactions" for more detail.
UNKNOWN [Initial status]
v ^
PENDING
v v
COMMITTED INVALID [Final statuses]
This status is not sampled atomically per handler: if this is called multiple times in a transaction handler, later calls may see more up to date values than earlier calls. Once a final state (COMMITTED or INVALID) has been reached, no further changes are possible.
Get the ID of latest transaction known to be committed.