public FlatBufferBuilder init(ByteBuffer existing_bb){
  bb=existing_bb;
  bb.clear();
  bb.order(ByteOrder.LITTLE_ENDIAN);
  minalign=1;
  space=bb.capacity();
  vtable_in_use=0;
  nested=false;
  finished=false;
  object_start=0;
  num_vtables=0;
  vector_num_elems=0;
  return this;
}

public FlatBufferBuilder init ( ByteBuffer existing_bb ) { bb = existing_bb ; bb . clear ( ) ; bb . order ( ByteOrder . LITTLE_ENDIAN ) ; minalign = 1 ; space = bb . capacity ( ) ; vtable_in_use = 0 ; nested = false ; finished = false ; object_start = 0 ; num_vtables = 0 ; vector_num_elems = 0 ; return this ; }
alternative initializer that allows reusing this object on an existing ` bytebuffer ` . this method resets the builder ' s internal state , but keeps objects that have been allocated for temporary storage .
