Description. This method sets the position within the blob at which to read or write data.
int setPos ( Uint64 pos )
The setPos() method takes a single parameter
pos (an unsigned 64-bit integer),
which is the position for reading or writing data. The value of
pos must be between
0 and the blob's current length.
“Sparse” blobs are not supported in the NDB API; in other words, there can be no unused data positions within a blob.
0 on success,