wf:[colon-separated list of features]
| bVALUE | Set the frame payload. If a masking key is present, the value is encoded automatically. |
| cINTEGER | Set the op code. This can either be an integer from 0-15, or be one of the following opcode names: continue, text, binary, close, ping, pong. |
| dOFFSET | Disconnect after OFFSET bytes. |
| iOFFSET,VALUE | Inject the specified value at the offset. |
| pOFFSET,SECONDS | Pause for SECONDS seconds after OFFSET bytes. SECONDS can be an integer or "f" to pause forever. |