an array of at least input_length*4/3 bytes
is some binary data
length of input in bytes
is an output parameter which says how many bytes of input were actually consumed. If less than input_length, then the range input[consumed:length] should be passed in later along with more input.
true iff this is the last input, in which case padding chars will be applied if needed
number of bytes written to output
Perform base64 encoding