Function esp_idf_sys::esp_tls_conn_read

pub unsafe extern "C" fn esp_tls_conn_read(
    tls: *mut esp_tls_t,
    data: *mut c_void,
    datalen: usize
) -> isize

@brief Read from specified tls connection into the buffer ‘data’.

@param[in] tls pointer to esp-tls as esp-tls handle. @param[in] data Buffer to hold read data. @param[in] datalen Length of data buffer.

@return - >0 if read operation was successful, the return value is the number of bytes actually read from the TLS/SSL connection. - 0 if read operation was not successful. The underlying connection was closed. - <0 if read operation was not successful, because either an error occured or an action must be taken by the calling process.