See: Description
| Interface | Description | 
|---|---|
| Bundle<T,CollectionT> | 
 An immutable collection of elements which are part of a  
PCollection. | 
| ExecutionDriver | 
 Drives the execution of a  
Pipeline by scheduling work. | 
| PipelineMessageReceiver | 
 Handles failures in the form of exceptions. 
 | 
| Class | Description | 
|---|---|
| StructuralKey<K> | 
 A (Key, Coder) pair that uses the structural value of the key (as provided by  
Coder.structuralValue(Object)) to perform equality and hashing. | 
| Enum | Description | 
|---|---|
| ExecutionDriver.DriverState | 
 The state of the driver. 
 |