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: text (the default), continue, binary, close, ping, pong.
dOFFSET Disconnect after OFFSET bytes.
[-]fin Set or un-set the fin bit.
iOFFSET,VALUE Inject the specified value at the offset.
kVALUE Set the masking key. The resulting value must be exactly 4 bytes long. The special form knone specifies that no key should be set, even if the mask bit is on.
lINTEGER Set the payload length in the frame header, regardless of the actual body length.
[-]mask Set or un-set the mask bit.
pOFFSET,SECONDS Pause for SECONDS seconds after OFFSET bytes. SECONDS can be an integer or "f" to pause forever.
rVALUE Set the raw frame payload. This diesables masking, even if the key is present.
[-]rsv1 Set or un-set the rsv1 bit.
[-]rsv2 Set or un-set the rsv2 bit.
[-]rsv3 Set or un-set the rsv3 bit.