Returns an immutable instance of [PromptimConfig].
public PromptimConfig build()Returns an immutable instance of [PromptimConfig]. Further updates to this [Builder] will not mutate the returned instance. The following fields are required:
.autoCommit()
.datasetName()
.devSplit()
.evaluators()
.messageIndex()
.numEpochs()
.taskDescription()
.testSplit()
.trainSplit()
IllegalStateException: if any required field is unset.