struct WireTableFrame

|WireTableFrame| stores the envelope header for each field in a table.

In their current wire format representation, a table is a vector of

envelopes. The table frame is the vector body portion of the table.

It is recommended that table frames are managed automatically using arenas.

Only directly construct a table frame when performance is key and arenas are

insufficient. Once created, a frame can only be used for one single table.