appendAll

Appends streams of one partition (or of several, when appendsAcrossPartitions), each atomically with its transport, and returns their outcomes in the same order. A partition's owner calls it with the appends it has queued (group commit): a backend may commit them together to share the round trips, as long as every outcome is what append would have returned: a stream the backend refuses (AppendOutcome.Rejected) fails alone, and a group whose commit is unknown is AppendOutcome.Unknown for each stream, never appended again one by one.

Several streams of one aggregate come in consecutive versions, in order (a kernel's batch of the commands its aggregate had queued). They commit as a prefix: once one of them does not commit, the aggregate's later streams are not appended, each AppendOutcome.Conflict at the version that stream's outcome leaves the aggregate at (notAppendedAfter), whether the backend tried them or not. By default the streams are appended one by one, an aggregate's later streams skipped once one did not commit.

Across partitions, each partition's streams take its sequences in the order they come, and one partition's outcomes do not depend on another's: a stream that does not commit stops only its own aggregate's later streams.