Wire Library Arduino Work Info

Wire.available() : Returns the number of bytes currently available for reading in the buffer.

The line used for transferring data between devices. wire library arduino

Reading data, conversely, is like requesting a file. The Arduino asks the slave for a specific number of bytes ( Wire.requestFrom(address, quantity) ), and then enters a waiting loop, extracting the data byte-by-byte like pearls on a string using Wire.read() . and then enters a waiting loop