The read function has been renamed to readAdvanced since it has slightly
different semantics than typical read functions, specifically regarding
the end-of-file. A higher level read function is implemented on top.
Now, API users may pass small buffers to the read function and
everything will work fine. This is done by re-decrypting the same
ciphertext record with each call to read() until the record is finished
being transmitted.
If the buffer supplied to read() is large enough, then any given
ciphertext record will only be decrypted once, since it decrypts
directly to the read() buffer and therefore does not need any memcpy. On
the other hand, if the buffer supplied to read() is small, then the
ciphertext is decrypted into a stack buffer, a subset is copied to the
read() buffer, and then the entire ciphertext record is saved for the
next call to read().
