Get the number of bytes (characters) available for writing in the serial buffer without blocking the write operation.
Serial.availableForWrite()
Serial: serial port object. See the list of available serial ports for each board on the Serial main page.
The number of bytes available to write.
LANGUAGE begin()
LANGUAGE end()
LANGUAGE read()
LANGUAGE peek()
LANGUAGE flush()
LANGUAGE print()
LANGUAGE println()
LANGUAGE write()
LANGUAGE SerialEvent()
LANGUAGE Stream.available()