[RTOS Stream Buffer API]
size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer );
Queries a stream buffer to see how much free space it contains, which is equal to the amount of data that can be sent to the stream buffer before it is full.
Stream buffer functionality is enabled by including the FreeRTOS/source/stream_buffer.c source file in the build.
xStreamBuffer The handle of the stream buffer being queried.
- The number of bytes that can be written to the stream buffer before the stream buffer would be full.